Constantine the Great Constantine the Great ( ; 27 February c . 27222 May 337 ) , also known as Constantine I or Saint Constantine , was Roman Emperor from 306 to 337 . Constantine was the son of Flavius Valerius Constantius , a Roman army officer , and his consort Helena . His father became " Caesar " , the deputy emperor in the west in 293 . Constantine was sent east , where he rose through the ranks to become a military tribune under the emperors Diocletian and Galerius . In 305 , Constantius was raised to the rank of " Augustus " , senior western emperor , and Constantine was recalled west to campaign under his father in Britannia . Acclaimed as emperor by the army after his father ' s death in 306 , Constantine emerged victorious in a series of civil wars against the emperors Maxentius and Licinius to become sole ruler of both west and east by 324 . As emperor , Constantine enacted many administrative , financial , social , and military reforms to strengthen the empire . The government was restructured and civil and military authority separated . A new gold coin , the solidus , was introduced to combat inflation . It would become the standard for Byzantine and European currencies for more than a thousand years . The first Roman emperor to convert to Christianity , Constantine played an influential role in the proclamation of the Edict of Milan , which decreed religious tolerance throughout the empire . He called the First Council of Nicaea in 325 , at which the Nicene Creed was professed by Christians . In military matters , the Roman army was reorganised to consist of mobile field units and garrison soldiers capable of countering internal threats and barbarian invasions . Constantine pursued successful campaigns against the tribes on the Roman frontiers — the Franks , the Alamanni , the Goths , and the Sarmatians — even resettling territories abandoned by his predecessors during the turmoil of the previous century . The age of Constantine marked a distinct epoch in the history of the Roman Empire . He built a new imperial residence at Byzantium and named it New Rome . However , in Constantine ' s honor , the Romans called it Constantinople , which would later be the capital of what is now known as the Byzantine Empire for over one thousand years . Because of this , he is thought of as the founder of the Byzantine Empire . His more immediate political legacy was that , in leaving the empire to his sons , he replaced Diocletian ' s tetrarchy with the principle of dynastic succession . His reputation flourished during the lifetime of his children and centuries after his reign . The medieval church upheld him as a paragon of virtue while secular rulers invoked him as a prototype , a point of reference , and the symbol of imperial legitimacy and identity . Beginning with the renaissance , there were more critical appraisals of his reign due to the rediscovery of anti - Constantinian sources . Critics portrayed him as a despotic tyrant . Trends in modern and recent scholarship attempted to balance the extremes of previous scholarship . Constantine — as the first Christian emperor — is a significant figure in the history of Christianity . The Church of the Holy Sepulchre , built on his orders at the purported site of Jesus ' tomb in Jerusalem , became the holiest place in Christendom . The Papacy claimed temporal power through Constantine . He is venerated as a saint by Orthodox Christians , Byzantine Catholics , and Anglicans . The Eastern churches hold his memory in particular esteem , regarding Constantine as isapostolos or " equal to the Apostles " . Sources . Constantine was a ruler of major historical importance , and he has always been a controversial figure . The fluctuations in Constantine ' s reputation reflect the nature of the ancient sources for his reign . These are abundant and detailed , but have been strongly influenced by the official propaganda of the period , and are often one - sided . There are no surviving histories or biographies dealing with Constantine ' s life and rule . The nearest replacement is Eusebius of Caesarea ' s " Vita Constantini " , a work that is a mixture of eulogy and hagiography . Written between 335 and circa 339 , the " Vita " extols Constantine ' s moral and religious virtues . The " Vita " creates a contentiously positive image of Constantine , and modern historians have frequently challenged its reliability . The fullest secular life of Constantine is the anonymous " Origo Constantini " . A work of uncertain date , the " Origo " focuses on military and political events , to the neglect of cultural and religious matters . Lactantius ' " De Mortibus Persecutorum " , a political Christian pamphlet on the reigns of Diocletian and the Tetrarchy , provides valuable but tendentious detail on Constantine ' s predecessors and early life . The ecclesiastical histories of Socrates , Sozomen , and Theodoret describe the ecclesiastic disputes of Constantine ' s later reign . Written during the reign of Theodosius II ( 408 – 50 ) , a century after Constantine ' s reign , these ecclesiastic historians obscure the events and theologies of the Constantinian period through misdirection , misrepresentation and deliberate obscurity . The contemporary writings of the orthodox Christian Athanasius and the ecclesiastical history of the Arian Philostorgius also survive , though their biases are no less firm . The epitome s of Aurelius Victor ( " De Caesaribus " ) , Eutropius ( " Breviarium " ) , Festus ( " Breviarium " ) , and the anonymous author of the " Epitome de Caesaribus " offer compressed secular political and military histories of the period . Although not Christian , the epitomes paint a favorable image of Constantine , but omit reference to Constantine ' s religious policies . The " Panegyrici Latini " , a collection of panegyric s from the late third and early fourth centuries , provide valuable information on the politics and ideology of the tetrarchic period and the early life of Constantine . Contemporary architecture , such as the Arch of Constantine in Rome and palaces in Gamzigrad and Córdoba , epigraphic remains , and the coinage of the era complement the literary sources . Early life . Flavius Valerius Constantinus , as he was originally named , was born in the city of Naissus , Dardania province of Moesia , in present - day Niš , Serbia , on 27 February of an uncertain year , probably near 272 . His father was Flavius Constantius , a native of Dardania province of Moesia ( later Dacia Ripensis ) . Constantius was a tolerant and politically skilled man . Constantine probably spent little time with his father . Constantius was an officer in the Roman army , part of the Emperor Aurelian ' s imperial bodyguard . Constantius advanced through the ranks , earning the governorship of Dalmatia from Emperor Diocletian , another of Aurelian ' s companions from Illyricum , in 284 or 285 . Constantine ' s mother was Helena , a Bithynian woman of low social standing . It is uncertain whether she was legally married to Constantius or merely his concubine . In July 285 , Diocletian declared Maximian , another colleague from Illyricum , his co - emperor . Each emperor would have his own court , his own military and administrative faculties , and each would rule with a separate praetorian prefect as chief lieutenant . Maximian ruled in the West , from his capitals at Mediolanum ( Milan , Italy ) or Augusta Treverorum ( Trier , Germany ) , while Diocletian ruled in the East , from Nicomedia ( İzmit , Turkey ) . The division was merely pragmatic : the Empire was called " indivisible " in official panegyric , and both emperors could move freely throughout the Empire . In 288 , Maximian appointed Constantius to serve as his praetorian prefect in Gaul . Constantius left Helena to marry Maximian ' s stepdaughter Theodora in 288 or 289 . Diocletian divided the Empire again in 293 , appointing two Caesars ( junior emperors ) to rule over further subdivisions of East and West . Each would be subordinate to their respective Augustus ( senior emperor ) but would act with supreme authority in his assigned lands . This system would later be called the Tetrarchy . Diocletian ' s first appointee for the office of Caesar was Constantius ; his second was Galerius , a native of Felix Romuliana . According to Lactantius , Galerius was a brutal , animalistic man . Although he shared the paganism of Rome ' s aristocracy , he seemed to them an alien figure , a semi - barbarian . On 1 March , Constantius was promoted to the office of Caesar , and dispatched to Gaul to fight the rebels Carausius and Allectus . In spite of meritocratic overtones , the Tetrarchy retained vestiges of hereditary privilege , and Constantine became the prime candidate for future appointment as Caesar as soon as his father took the position . Constantine went to the court of Diocletian , where he lived as his father ' s heir presumptive . In the East . Constantine received a formal education at Diocletian ' s court , where he learned Latin literature , Greek , and philosophy . The cultural environment in Nicomedia was open , fluid and socially mobile , and Constantine could mix with intellectuals both pagan and Christian . He may have attended the lectures of Lactantius , a Christian scholar of Latin in the city . Because Diocletian did not completely trust Constantius — none of the Tetrarchs fully trusted their colleagues — Constantine was held as something of a hostage , a tool to ensure Constantius ' best behavior . Constantine was nonetheless a prominent member of the court : he fought for Diocletian and Galerius in Asia , and served in a variety of tribunates ; he campaigned against barbarians on the Danube in 296 , and fought the Persians under Diocletian in Syria ( 297 ) and under Galerius in Mesopotamia ( 298 – 99 ) . By late 305 , he had become a tribune of the first order , a " tribunus ordinis primi " . Constantine had returned to Nicomedia from the eastern front by the spring of 303 , in time to witness the beginnings of Diocletian ' s " Great Persecution " , the most severe persecution of Christians in Roman history . In late 302 , Diocletian and Galerius sent a messenger to the oracle of Apollo at Didyma with an inquiry about Christians . Constantine could recall his presence at the palace when the messenger returned , when Diocletian accepted his court ' s demands for universal persecution . On 23 February 303 , Diocletian ordered the destruction of Nicomedia ' s new church , condemned its scriptures to the flames , and had its treasures seized . In the months that followed , churches and scriptures were destroyed , Christians were deprived of official ranks , and priests were imprisoned . It is unlikely that Constantine played any role in the persecution . In his later writings he would attempt to present himself as an opponent of Diocletian ' s " sanguinary edicts " against the " worshippers of God " , but nothing indicates that he opposed it effectively at the time . Although no contemporary Christian challenged Constantine for his inaction during the persecutions , it remained a political liability throughout his life . On 1 May 305 , Diocletian , as a result of a debilitating sickness taken in the winter of 304 – 5 , announced his resignation . In a parallel ceremony in Milan , Maximian did the same . Lactantius states that Galerius manipulated the weakened Diocletian into resigning , and forced him to accept Galerius ' allies in the imperial succession . According to Lactantius , the crowd listening to Diocletian ' s resignation speech believed , until the very last moment , that Diocletian would choose Constantine and Maxentius ( Maximian ' s son ) as his successors . It was not to be : Constantius and Galerius were promoted to Augusti , while Severus and Maximin were appointed their Caesars respectively . Constantine and Maxentius were ignored . Some of the ancient sources detail plots that Galerius made on Constantine ' s life in the months following Diocletian ' s abdication . They assert that Galerius assigned Constantine to lead an advance unit in a cavalry charge through a swamp on the middle Danube , made him enter into single combat with a lion , and attempted to kill him in hunts and wars . Constantine always emerged victorious : the lion emerged from the contest in a poorer condition than Constantine ; Constantine returned to Nicomedia from the Danube with a Sarmatian captive to drop at Galerius ' feet . It is uncertain how much these tales can be trusted . In the West . Constantine recognized the implicit danger in remaining at Galerius ' court , where he was held as a virtual hostage . His career depended on being rescued by his father in the west . Constantius was quick to intervene . In the late spring or early summer of 305 , Constantius requested leave for his son to help him campaign in Britain . After a long evening of drinking , Galerius granted the request . Constantine ' s later propaganda describes how he fled the court in the night , before Galerius could change his mind . He rode from post - house to post - house at high speed , hamstringing every horse in his wake . By the time Galerius awoke the following morning , Constantine had fled too far to be caught . Constantine joined his father in Gaul , at Bononia ( Boulogne ) before the summer of 305 . From Bononia they crossed the Channel to Britain and made their way to Eboracum ( York ) , capital of the province of Britannia Secunda and home to a large military base . Constantine was able to spend a year in northern Britain at his father ' s side , campaigning against the Picts beyond Hadrian ' s Wall in the summer and autumn . Constantius ' s campaign , like that of Septimius Severus before it , probably advanced far into the north without achieving great success . Constantius had become severely sick over the course of his reign , and died on 25 July 306 in Eboracum ( York ) . Before dying , he declared his support for raising Constantine to the rank of full Augustus . The Alamannic king Chrocus , a barbarian taken into service under Constantius , then proclaimed Constantine as Augustus . The troops loyal to Constantius ' memory followed him in acclamation . Gaul and Britain quickly accepted his rule ; Iberia , which had been in his father ' s domain for less than a year , rejected it . Constantine sent Galerius an official notice of Constantius ' s death and his own acclamation . Along with the notice , he included a portrait of himself in the robes of an Augustus . The portrait was wreathed in bay . He requested recognition as heir to his father ' s throne , and passed off responsibility for his unlawful ascension on his army , claiming they had " forced it upon him " . Galerius was put into a fury by the message ; he almost set the portrait on fire . His advisers calmed him , and argued that outright denial of Constantine ' s claims would mean certain war . Galerius was compelled to compromise : he granted Constantine the title " Caesar " rather than " Augustus " ( the latter office went to Severus instead ) . Wishing to make it clear that he alone gave Constantine legitimacy , Galerius personally sent Constantine the emperor ' s traditional purple robes . Constantine accepted the decision , knowing that it would remove doubts as to his legitimacy . Early rule . Constantine ' s share of the Empire consisted of Britain , Gaul , and Spain . He therefore commanded one of the largest Roman armies , stationed along the important Rhine frontier . After his promotion to emperor , Constantine remained in Britain , and secured his control in the northwestern diocese s . He completed the reconstruction of military bases begun under his father ' s rule , and ordered the repair of the region ' s roadways . He soon left for Augusta Treverorum ( Trier ) in Gaul , the Tetrarchic capital of the northwestern Roman Empire . The Franks , after learning of Constantine ' s acclamation , invaded Gaul across the lower Rhine over the winter of 306 – 7 . Constantine drove them back beyond the Rhine and captured two of their kings , Ascaric and Merogaisus . The kings and their soldiers were fed to the beasts of Trier ' s amphitheater in the " adventus " ( arrival ) celebrations that followed . Constantine began a major expansion of Trier . He strengthened the circuit wall around the city with military towers and fortified gates , and began building a palace complex in the northeastern part of the city . To the south of his palace , he ordered the construction of a large formal audience hall , and a massive imperial bathhouse . Constantine sponsored many building projects across Gaul during his tenure as emperor of the West , especially in Augustodunum ( Autun ) and Arelate ( Arles ) . According to Lactantius , Constantine followed his father in following a tolerant policy towards Christianity . Although not yet a Christian , he probably judged it a more sensible policy than open persecution , and a way to distinguish himself from the " great persecutor " , Galerius . Constantine decreed a formal end to persecution , and returned to Christians all they had lost during the persecutions . Because Constantine was still largely untried and had a hint of illegitimacy about him , he relied on his father ' s reputation in his early propaganda : the earliest panegyrics to Constantine give as much coverage to his father ' s deeds as to those of Constantine himself . Constantine ' s military skill and building projects soon gave the panegyrist the opportunity to comment favorably on the similarities between father and son , and Eusebius remarked that Constantine was a " renewal , as it were , in his own person , of his father ' s life and reign " . Constantinian coinage , sculpture and oratory also shows a new tendency for disdain towards the " barbarians " beyond the frontiers . After Constantine ' s victory over the Alemanni , he minted a coin issue depicting weeping and begging Alemannic tribesmen — " The Alemanni conquered " — beneath the phrase " Romans ' rejoicing " . There was little sympathy for these enemies . As his panegyrist declared : " It is a stupid clemency that spares the conquered foe . " Maxentius ' rebellion . Following Galerius ' recognition of Constantine as caesar , Constantine ' s portrait was brought to Rome , as was customary . Maxentius mocked the portrait ' s subject as the son of a harlot , and lamented his own powerlessness . Maxentius , jealous of Constantine ' s authority , seized the title of emperor on 28 October 306 . Galerius refused to recognize him , but failed to unseat him . Galerius sent Severus against Maxentius , but during the campaign , Severus ' armies , previously under command of Maxentius ' father Maximian , defected , and Severus was seized and imprisoned . Maximian , brought out of retirement by his son ' s rebellion , left for Gaul to confer with Constantine in late 307 . He offered to marry his daughter Fausta to Constantine , and elevate him to Augustan rank . In return , Constantine would reaffirm the old family alliance between Maximian and Constantius , and offer support to Maxentius ' cause in Italy . Constantine accepted , and married Fausta in Trier in late summer 307 . Constantine now gave Maxentius his meagre support , offering Maxentius political recognition . Constantine remained aloof from the Italian conflict , however . Over the spring and summer of 307 , he had left Gaul for Britain to avoid any involvement in the Italian turmoil ; now , instead of giving Maxentius military aid , he sent his troops against Germanic tribes along the Rhine . In 308 , he raided the territory of the Bructeri , and made a bridge across the Rhine at Colonia Agrippinensium ( Cologne ) . In 310 , he marched to the northern Rhine and fought the Franks . When not campaigning , he toured his lands advertising his benevolence , and supporting the economy and the arts . His refusal to participate in the war increased his popularity among his people , and strengthened his power base in the West . Maximian returned to Rome in the winter of 307 – 8 , but soon fell out with his son . In early 308 , after a failed attempt to usurp Maxentius ' title , Maximian returned to Constantine ' s court . On 11 November 308 , Galerius called a general council at the military city of Carnuntum ( Petronell - Carnuntum , Austria ) to resolve the instability in the western provinces . In attendance were Diocletian , briefly returned from retirement , Galerius , and Maximian . Maximian was forced to abdicate again and Constantine was again demoted to Caesar . Licinius , one of Galerius ' old military companions , was appointed Augustus of the west . The new system did not last long : Constantine refused to accept the demotion , and continued to style himself as Augustus on his coinage , even as other members of the Tetrarchy referred to him as a Caesar on theirs . Maximinus Daia was frustrated that he had been passed over for promotion while the newcomer Licinius had been raised to the office of Augustus , and demanded that Galerius promote him . Galerius offered to call both Maximinus and Constantine " sons of the Augusti " , but neither accepted the new title . By the spring of 310 , Galerius was referring to both men as Augusti . Maximian ' s rebellion . In 310 , a dispossessed and power - hungry Maximian rebelled against Constantine while Constantine was away campaigning against the Franks . Maximian had been sent south to Arles with a contingent of Constantine ' s army , in preparation for any attacks by Maxentius in southern Gaul . He announced that Constantine was dead , and took up the imperial purple . In spite of a large donative pledge to any who would support him as emperor , most of Constantine ' s army remained loyal to their emperor , and Maximian was soon compelled to leave . Constantine soon heard of the rebellion , abandoned his campaign against the Franks , and marched his army up the Rhine . At Cabillunum ( Chalon - sur - Saône ) , he moved his troops onto waiting boats to row down the slow waters of the Saône to the quicker waters of the Rhone . He disembarked at Lugdunum ( Lyon ) . Maximian fled to Massilia ( Marseille ) , a town better able to withstand a long siege than Arles . It made little difference , however , as loyal citizens opened the rear gates to Constantine . Maximian was captured and reproved for his crimes . Constantine granted some clemency , but strongly encouraged his suicide . In July 310 , Maximian hanged himself . In spite of the earlier rupture in their relations , Maxentius was eager to present himself as his father ' s devoted son after his death . He began minting coins with his father ' s deified image , proclaiming his desire to avenge Maximian ' s death . Constantine initially presented the suicide as an unfortunate family tragedy . By 311 , however , he was spreading another version . According to this , after Constantine had pardoned him , Maximian planned to murder Constantine in his sleep . Fausta learned of the plot and warned Constantine , who put a eunuch in his own place in bed . Maximian was apprehended when he killed the eunuch and was offered suicide , which he accepted . Along with using propaganda , Constantine instituted a " damnatio memoriae " on Maximian , destroying all inscriptions referring to him and eliminating any public work bearing his image . The death of Maximian required a shift in Constantine ' s public image . He could no longer rely on his connection to the elder emperor Maximian , and needed a new source of legitimacy . In a speech delivered in Gaul on 25 July 310 , the anonymous orator reveals a previously unknown dynastic connection to Claudius II , a third - century emperor famed for defeating the Goths and restoring order to the empire . Breaking away from tetrarchic models , the speech emphasizes Constantine ' s ancestral prerogative to rule , rather than principles of imperial equality . The new ideology expressed in the speech made Galerius and Maximian irrelevant to Constantine ' s right to rule . Indeed , the orator emphasizes ancestry to the exclusion of all other factors : " No chance agreement of men , nor some unexpected consequence of favor , made you emperor , " the orator declares to Constantine . The oration also moves away from the religious ideology of the Tetrarchy , with its focus on twin dynasties of Jupiter and Hercules . Instead , the orator proclaims that Constantine experienced a divine vision of Apollo and Victory granting him laurel wreaths of health and a long reign . In the likeness of Apollo Constantine recognized himself as the saving figure to whom would be granted " rule of the whole world " , as the poet Virgil had once foretold . The oration ' s religious shift is paralleled by a similar shift in Constantine ' s coinage . In his early reign , the coinage of Constantine advertised Mars as his patron . From 310 on , Mars was replaced by Sol Invictus , a god conventionally identified with Apollo . There is little reason to believe that either the dynastic connection or the divine vision are anything other than fiction , but their proclamation strengthened Constantine ' s claims to legitimacy and increased his popularity among the citizens of Gaul . Civil wars . War against Maxentius . By the middle of 310 , Galerius had become too ill to involve himself in imperial politics . His final act survives : a letter to the provincials posted in Nicomedia on 30 April 311 , proclaiming an end to the persecutions , and the resumption of religious toleration . He died soon after the edict ' s proclamation , destroying what little remained of the tetrarchy . Maximin mobilized against Licinius , and seized Asia Minor . A hasty peace was signed on a boat in the middle of the Bosphorus . While Constantine toured Britain and Gaul , Maxentius prepared for war . He fortified northern Italy , and strengthened his support in the Christian community by allowing it to elect a new Bishop of Rome , Eusebius . Maxentius ' rule was nevertheless insecure . His early support dissolved in the wake of heightened tax rates and depressed trade ; riots broke out in Rome and Carthage ; and Domitius Alexander was able to briefly usurp his authority in Africa . By 312 , he was a man barely tolerated , not one actively supported , even among Christian Italians . In the summer of 311 , Maxentius mobilized against Constantine while Licinius was occupied with affairs in the East . He declared war on Constantine , vowing to avenge his father ' s " murder " . To prevent Maxentius from forming an alliance against him with Licinius , Constantine forged his own alliance with Licinius over the winter of 311 – 12 , and offered him his sister Constantia in marriage . Maximin considered Constantine ' s arrangement with Licinius an affront to his authority . In response , he sent ambassadors to Rome , offering political recognition to Maxentius in exchange for a military support . Maxentius accepted . According to Eusebius , inter - regional travel became impossible , and there was military buildup everywhere . There was " not a place where people were not expecting the onset of hostilities every day " . Constantine ' s advisers and generals cautioned against preemptive attack on Maxentius ; even his soothsayers recommended against it , stating that the sacrifices had produced unfavorable omens . Constantine , with a spirit that left a deep impression on his followers , inspiring some to believe that he had some form of supernatural guidance , ignored all these cautions . Early in the spring of 312 , Constantine crossed the Cottian Alps with a quarter of his army , a force numbering about 40 , 000 . The first town his army encountered was Segusium ( Susa , Italy ) , a heavily fortified town that shut its gates to him . Constantine ordered his men to set fire to its gates and scale its walls . He took the town quickly . Constantine ordered his troops not to loot the town , and advanced with them into northern Italy . At the approach to the west of the important city of Augusta Taurinorum ( Turin , Italy ) , Constantine met a large force of heavily armed Maxentian cavalry . In the ensuing battle Constantine ' s army encircled Maxentius ' cavalry , flanked them with his own cavalry , and dismounted them with blows from his soldiers ' iron - tipped clubs . Constantine ' s armies emerged victorious . Turin refused to give refuge to Maxentius ' retreating forces , opening its gates to Constantine instead . Other cities of the north Italian plain sent Constantine embassies of congratulation for his victory . He moved on to Milan , where he was met with open gates and jubilant rejoicing . Constantine rested his army in Milan until mid - summer 312 , when he moved on to Brixia ( Brescia ) . Brescia ' s army was easily dispersed , and Constantine quickly advanced to Verona , where a large Maxentian force was camped . Ruricius Pompeianus , general of the Veronese forces and Maxentius ' praetorian prefect , was in a strong defensive position , since the town was surrounded on three sides by the Adige . Constantine sent a small force north of the town in an attempt to cross the river unnoticed . Ruricius sent a large detachment to counter Constantine ' s expeditionary force , but was defeated . Constantine ' s forces successfully surrounded the town and laid siege . Ruricius gave Constantine the slip and returned with a larger force to oppose Constantine . Constantine refused to let up on the siege , and sent only a small force to oppose him . In the desperately fought encounter that followed , Ruricius was killed and his army destroyed . Verona surrendered soon afterwards , followed by Aquileia , Mutina ( Modena ) , and Ravenna . The road to Rome was now wide open to Constantine . Maxentius prepared for the same type of war he had waged against Severus and Galerius : he sat in Rome and prepared for a siege . He still controlled Rome ' s praetorian guards , was well - stocked with African grain , and was surrounded on all sides by the seemingly impregnable Aurelian Walls . He ordered all bridges across the Tiber cut , reportedly on the counsel of the gods , and left the rest of central Italy undefended ; Constantine secured that region ' s support without challenge . Constantine progressed slowly along the " Via Flaminia " , allowing the weakness of Maxentius to draw his regime further into turmoil . Maxentius ' support continued to weaken : at chariot races on 27 October , the crowd openly taunted Maxentius , shouting that Constantine was invincible . Maxentius , no longer certain that he would emerge from a siege victorious , built a temporary boat bridge across the Tiber in preparation for a field battle against Constantine . On 28 October 312 , the sixth anniversary of his reign , he approached the keepers of the Sibylline Books for guidance . The keepers prophesied that , on that very day , " the enemy of the Romans " would die . Maxentius advanced north to meet Constantine in battle . Constantine ' s army adopts the Christian cross . Maxentius organized his forces — still twice the size of Constantine ' s — in long lines facing the battle plain , with their backs to the river . Constantine ' s army arrived at the field bearing unfamiliar symbols on either its standards or its soldiers ' shields . According to Lactantius , Constantine was visited by a dream the night before the battle , wherein he was advised " to mark the heavenly sign of God on the shields of his soldiers . . . by means of a slanted letter X with the top of its head bent round , he marked Christ on their shields . " Eusebius describes another version , where , while marching at midday , " he saw with his own eyes in the heavens a trophy of the cross arising from the light of the sun , carrying the message , " In Hoc Signo Vinces " or " with this sign , you will conquer " ; in Eusebius ' s account , Constantine had a dream the following night , in which Christ appeared with the same heavenly sign , and told him to make a standard , the " labarum " , for his army in that form . Eusebius is vague about when and where these events took place , but it enters his narrative before the war against Maxentius begins . Eusebius describes the sign as Chi ( Χ ) traversed by Rho ( Ρ ) : ☧ , a symbol representing the first two letters of the Greek spelling of the word " Christos " or Christ . The Eusebian description of the vision has been explained as a type of solar halo called a " sun dog " , a meteorological phenomenon which can produce similar effects . In 315 a medallion was issued at Ticinum showing Constantine wearing a helmet emblazoned with the " Chi Rho " , and coins issued at Siscia in 317 / 18 repeat the image . The figure was otherwise rare , however , and is uncommon in imperial iconography and propaganda before the 320s . Constantine deployed his own forces along the whole length of Maxentius ' line . He ordered his cavalry to charge , and they broke Maxentius ' cavalry . He then sent his infantry against Maxentius ' infantry , pushing many into the Tiber where they were slaughtered and drowned . The battle was brief : Maxentius ' troops were broken before the first charge . Maxentius ' horse guards and praetorians initially held their position , but broke under the force of a Constantinian cavalry charge ; they also broke ranks and fled to the river . Maxentius rode with them , and attempted to cross the bridge of boats , but he was pushed by the mass of his fleeing soldiers into the Tiber , and drowned . In Rome . Constantine entered Rome on 29 October . He staged a grand " adventus " in the city , and was met with popular jubilation . Maxentius ' body was fished out of the Tiber and decapitated . His head was paraded through the streets for all to see . After the ceremonies , Maxentius ' disembodied head was sent to Carthage ; at this Carthage would offer no further resistance . Unlike his predecessors , Constantine neglected to make the trip to the Capitoline Hill and perform customary sacrifices at the Temple of Jupiter . He did , however , choose to honor the Senatorial Curia with a visit , where he promised to restore its ancestral privileges and give it a secure role in his reformed government : there would be no revenge against Maxentius ' supporters . In response , the Senate decreed him " title of the first name " , which meant his name would be listed first in all official documents , and acclaimed him as " the greatest Augustus " . He issued decrees returning property lost under Maxentius , recalling political exiles , and releasing Maxentius ' imprisoned opponents . An extensive propaganda campaign followed , during which Maxentius ' image was systematically purged from all public places . Maxentius was written up as a " tyrant " , and set against an idealized image of the " liberator " , Constantine . Eusebius , in his later works , is the best representative of this strand of Constantinian propaganda . Maxentius ' rescripts were declared invalid , and the honors Maxentius had granted to leaders of the Senate were invalidated . Constantine also attempted to remove Maxentius ' influence on Rome ' s urban landscape . All structures built by Maxentius were re - dedicated to Constantine , including the Temple of Romulus and the Basilica of Maxentius . At the focal point of the basilica , a stone statue of Constantine holding the Christian " labarum " in its hand was erected . Its inscription bore the message the statue had already made clear : By this sign Constantine had freed Rome from the yoke of the tyrant . Where he did not overwrite Maxentius ' achievements , Constantine upstaged them : the Circus Maximus was redeveloped so that its total seating capacity was twenty - five times larger than that of Maxentius ' racing complex on the Via Appia . Maxentius ' strongest supporters in the military were neutralized when the Praetorian Guard and Imperial Horse Guard ( " equites singulares " ) were disbanded . Their tombstones were ground up and put to use in a basilica on the Via Labicana . On 9 November 312 , barely two weeks after Constantine captured the city , the former base of the Imperial Horse Guard was chosen for redevelopment into the Lateran Basilica . The Legio II Parthica was removed from Alba ( Albano Laziale ) , and the remainder of Maxentius ' armies were sent to do frontier duty on the Rhine . Wars against Licinius . In the following years , Constantine gradually consolidated his military superiority over his rivals in the crumbling Tetrarchy . In 313 , he met Licinius in Milan to secure their alliance by the marriage of Licinius and Constantine ' s half - sister Constantia . During this meeting , the emperors agreed on the so - called Edict of Milan , officially granting full tolerance to Christianity and all religions in the Empire . The document had special benefits for Christians , legalizing their religion and granting them restoration for all property seized during Diocletian ' s persecution . It repudiates past methods of religious coercion and used only general terms to refer to the divine sphere — " Divinity " and " Supreme Divinity " , " summa divinitas " . The conference was cut short , however , when news reached Licinius that his rival Maximin had crossed the Bosporus and invaded European territory . Licinius departed and eventually defeated Maximin , gaining control over the entire eastern half of the Roman Empire . Relations between the two remaining emperors deteriorated , as Constantine suffered an assassination attempt at the hands of a character that Licinius wanted elevated to the rank of Caesar ; Licinius , for his part had Constantine ' s statues in Emona and Pannonia destroyed . In either 314 or 316 the two Augusti fought against one another at the Battle of Cibalae , with Constantine being victorious . They clashed again at the Battle of Mardia in 317 , and agreed to a settlement in which Constantine ' s sons Crispus and Constantine II , and Licinius ' son Licinianus were made " caesars " . After this arrangement , Constantine ruled the dioceses of Pannonia and Macedonia and took residence at Sirmium , from whence he could wage war on the Goths and Sarmatians in 322 , and on the Goths in 323 . In the year 320 , Licinius allegedly reneged on the religious freedom promised by the Edict of Milan in 313 and began to oppress Christians anew , generally without bloodshed , but resorting to confiscations and sacking of Christian office - holders . Although this characterization of Licinius as anti - Christian is somewhat doubtful , the fact is that he seems to have been far less open in his support of Christianity than Constantine . Therefore Licinius was prone to see the Church as a force more loyal to Constantine than to the Imperial system in general - the explanation offered by the Church historian Sozomen . This dubious arrangement eventually became a challenge to Constantine in the West , climaxing in the great civil war of 324 . Licinius , aided by Goth mercenaries , represented the past and the ancient Pagan faiths . Constantine and his Franks marched under the standard of the " labarum " , and both sides saw the battle in religious terms . Outnumbered , but fired by their zeal , Constantine ' s army emerged victorious in the Battle of Adrianople . Licinius fled across the Bosphorus and appointed Martius Martinianus , the commander of his bodyguard , as Caesar , but Constantine next won the Battle of the Hellespont , and finally the Battle of Chrysopolis on 18 September 324 . Licinius and Martinianus surrendered to Constantine at Nicomedia on the promise their lives would be spared : they were sent to live as private citizens in Thessalonica and Cappadocia respectively , but in 325 Constantine accused Licinius of plotting against him and had them both arrested and hanged ; Licinius ' s son ( the son of Constantine ' s half - sister ) was also killed . Thus Constantine became the sole emperor of the Roman Empire . Later rule . Foundation of Constantinople . Licinius ' defeat came to represent the defeat of a rival center of Pagan and Greek - speaking political activity in the East , as opposed to the Christian and Latin - speaking Rome , and it was proposed that a new Eastern capital should represent the integration of the East into the Roman Empire as a whole , as a center of learning , prosperity , and cultural preservation for the whole of the Eastern Roman Empire . Among the various locations proposed for this alternative capital , Constantine appears to have toyed earlier with Serdica ( present - day Sofia ) , as he was reported saying that " " Serdica is my Rome " " . Sirmium and Thessalonica were also considered . Eventually , however , Constantine decided to work on the Greek city of Byzantium , which offered the advantage of having already been extensively rebuilt on Roman patterns of urbanism , during the preceding century , by Septimius Severus and Caracalla , who had already acknowledged its strategic importance . The city was then renamed " Constantinopolis " ( " Constantine ' s City " or Constantinople in English ) , and issued special commemorative coins in 330 to honor the event . The new city was protected by the relics of the True Cross , the Rod of Moses and other holy relics , though a cameo now at the Hermitage Museum also represented Constantine crowned by the tyche of the new city . The figures of old gods were either replaced or assimilated into a framework of Christian symbolism . Constantine built the new Church of the Holy Apostles on the site of a temple to Aphrodite . Generations later there was the story that a divine vision led Constantine to this spot , and an angel no one else could see , led him on a circuit of the new walls . The capital would often be compared to the ' old ' Rome as " Nova Roma Constantinopolitana " , the " New Rome of Constantinople " . Religious policy . Constantine is perhaps best known for being the first Christian Roman emperor . In February 313 , Constantine met with Licinius in Milan , where they developed the Edict of Milan . The edict stated that Christians should be allowed to follow the faith without oppression . This removed penalties for professing Christianity , under which many had been martyred in persecutions of Christians , and returned confiscated Church property . The edict protected from religious persecution not only Christians but all religions , allowing anyone to worship whichever deity they chose . A similar edict had been issued in 311 by Galerius , then senior emperor of the Tetrarchy ; Galerius ' edict granted Christians the right to practice their religion but did not restore any property to them . The Edict of Milan included several clauses which stated that all confiscated churches would be returned as well as other provisions for previously persecuted Christians . Scholars debate whether Constantine adopted his mother St . Helena ' s Christianity in his youth , or whether he adopted it gradually over the course of his life . Constantine would retain the title of " pontifex maximus " until his death , a title emperors bore as heads of the pagan priesthood , as would his Christian successors on to Gratian ( " r " . 375 – 83 ) . According to Christian writers , Constantine was over 40 when he finally declared himself a Christian , writing to Christians to make clear that he believed he owed his successes to the protection of the Christian High God alone . Throughout his rule , Constantine supported the Church financially , built basilicas , granted privileges to clergy ( e . g . exemption from certain taxes ) , promoted Christians to high office , and returned property confiscated during the Diocletianic persecution . His most famous building projects include the Church of the Holy Sepulchre , and Old Saint Peter ' s Basilica . However , Constantine certainly did not patronize Christianity alone . After gaining victory in the Battle of the Milvian Bridge ( 312 ) , a triumphal arch — the Arch of Constantine — was built ( 315 ) to celebrate his triumph . The arch is decorated with images of the goddess Victoria . At the time of its dedication , sacrifices to gods like Apollo , Diana , and Hercules were made . Absent from the Arch are any depictions of Christian symbolism . However , as the Arch was commissioned by the Senate , the absence of Christian symbols may reflect the role of the Curia at the time as a pagan redoubt . Later in 321 , Constantine instructed that Christians and non - Christians should be united in observing the venerable day of the sun , referencing the sun - worship that Aurelian had established as an official cult . Furthermore , and long after his oft alleged conversion to Christianity , Constantine ' s coinage continued to carry the symbols of the sun . Even after the pagan gods had disappeared from the coinage , Christian symbols appeared only as Constantine ' s " personal " attributes : the chi rho between his hands or on his labarum , but never on the coin itself . Even when Constantine dedicated the new capital of Constantinople , which became the seat of Byzantine Christianity for a millennium , he did so wearing the Apollo nian sun - rayed Diadem ; no Christian symbols were present at this dedication . The reign of Constantine established a precedent for the position of the emperor as having great influence and ultimate regulatory authority within the religious discussions involving the early Christian councils of that time , e . g . , most notably the dispute over Arianism , and the nature of God . Constantine himself disliked the risks to societal stability that religious disputes and controversies brought with them , preferring where possible to establish an orthodoxy . One way in which Constantine used his influence over the early Church councils was to seek to establish a consensus over the oft debated and argued issue over the nature of God . Most notably , from 313 – 316 bishops in North Africa struggled with other Christian bishops who had been ordained by Donatus in opposition to Caecilian . The African bishops could not come to terms and the Donatists asked Constantine to act as a judge in the dispute . Three regional Church councils and another trial before Constantine all ruled against Donatus and the Donatism movement in North Africa . In 317 Constantine issued an edict to confiscate Donatist church property and to send Donatist clergy into exile . More significantly , in 325 he summoned the Council of Nicaea , effectively the first Ecumenical Council ( unless the Council of Jerusalem is so classified ) . The Council of Nicaea is most known for its dealing with Arianism and for instituting the Nicene Creed . Constantine enforced the prohibition of the First Council of Nicaea against celebrating the Lord ' s Supper on the day before the Jewish Passover ( 14 " Nisan " ) ( see Quartodecimanism and Easter controversy ) . This marked a definite break of Christianity from the Judaic tradition . From then on the Roman Julian Calendar , a solar calendar , was given precedence over the lunar Hebrew Calendar among the Christian churches of the Roman Empire . Constantine made new laws regarding the Jews . They were forbidden to own Christian slaves or to circumcise their slaves . Administrative reforms . Beginning in the mid - 3rd century the emperors began to favor members of the equestrian order over senators , who had had a monopoly on the most important offices of state . Senators were stripped of the command of legions and most provincial governorships ( as it was felt that they lacked the specialized military upbringing needed in an age of acute defense needs ) , such posts being given to equestrians by Diocletian and his colleagues — following a practice enforced piecemeal by their predecessors . The emperors however , still needed the talents and the help of the very rich , who were relied on to maintain social order and cohesion by means of a web of powerful influence and contacts at all levels . Exclusion of the old senatorial aristocracy threatened this arrangement . In 326 , Constantine reversed this pro - equestrian trend , raising many administrative positions to senatorial rank and thus opening these offices to the old aristocracy , and at the same time elevating the rank of already existing equestrians office - holders to senator , degrading the equestrian order — at least as a bureaucratic rank — in the process , so that by the end of the 4th century the title of " perfectissimus " was granted only to mid - low officials . By the new Constantinian arrangement , one could become a senator , either by being elected praetor or ( in most cases ) by fulfilling a function of senatorial rank : from then on , holding of actual power and social status were melded together into a joint imperial hierarchy . At the same time , Constantine gained with this the support of the old nobility , as the Senate was allowed itself to elect praetors and quaestors , in place of the usual practice of the emperors directly creating new magistrates ( " adlectio " ) . In one inscription in honor of city prefect ( 336 – 37 ) Ceionius Rufus Albinus , it was written that Constantine had restored the Senate " the " auctoritas " it had lost at Caesar ' s time " . The Senate as a body remained devoid of any significant power ; nevertheless , the senators , who had been marginalized as potential holders of imperial functions during the 3rd century , could now dispute such positions alongside more upstart bureaucrats . Some modern historians see in those administrative reforms an attempt by Constantine at reintegrating the senatorial order into the imperial administrative elite to counter the possibility of alienating pagan senators from a Christianized imperial rule ; however , such an interpretation remains conjectural , given the fact that we do not have the precise numbers about pre - Constantine conversions to Christianity in the old senatorial milieu — some historians suggesting that early conversions among the old aristocracy were more numerous than previously supposed . Constantine ' s reforms had to do only with the civilian administration : the military chiefs , who since the Crisis of the Third Century had risen from the ranks , remained outside the senate , in which they were included only by Constantine ' s children . Monetary reforms . After the runaway inflation of the third century , associated with the production of fiat money to pay for public expenses , Diocletian had tried unsuccessfully to reestablish trustworthy minting of silver and billon coins . The failure of the various Diocletianic attempts at the restoration of a functioning silver coin resided in the fact that the silver currency was overvalued in terms of its actual metal content , and therefore could only circulate at much discounted rates . Minting of the Diocletianic " pure " silver " argenteus " ceased , therefore , soon after 305 , while the billon currency continued to be used until the 360s . From the early 300s on , Constantine forsook any attempts at restoring the silver currency , preferring instead to concentrate on minting large quantities of good standard gold pieces — the solidus , 72 of which made a pound of gold . New ( and highly debased ) silver pieces would continue to be issued during Constantine ' s later reign and after his death , in a continuous process of retariffing , until this billon minting eventually ceased , " de jure " , in 367 , with the silver piece being " de facto " continued by various denominations of bronze coins , the most important being the " centenionalis " . These bronze pieces continued to be devalued , assuring the possibility of keeping fiduciary minting alongside a gold standard . The anonymous author of the possibly contemporary treatise on military affairs " De Rebus Bellicis " held that , as a consequence of this monetary policy , the rift between classes widened : the rich benefited from the stability in purchasing power of the gold piece , while the poor had to cope with ever - degrading bronze pieces . Later emperors like Julian the Apostate tried to present themselves as advocates of the " humiles " by insisting on trustworthy mintings of the bronze currency . Constantine ' s monetary policy were closely associated with his religious ones , in that increased minting was associated with measures of confiscation — taken since 331 and closed in 336 — of all gold , silver and bronze statues from pagan temples , who were declared as imperial property and , as such , as monetary assets . Two imperial commissioners for each province had the task of getting hold of the statues and having them melded for immediate minting — with the exception of a number of bronze statues who were used as public monuments for the beautification of the new capital in Constantinople . Executions of Crispus and Fausta . On some date between 15 May and 17 June 326 , Constantine had his eldest son Crispus , by Minervina , seized and put to death by " cold poison " at Pola ( Pula , Croatia ) . In July , Constantine had his wife , the Empress Fausta , killed at the behest of his mother , Helena . Fausta was left to die in an over - heated bath . Their names were wiped from the face of many inscriptions , references to their lives in the literary record were erased , and the memory of both was condemned . Eusebius , for example , edited praise of Crispus out of later copies of his " Historia Ecclesiastica " , and his " Vita Constantini " contains no mention of Fausta or Crispus at all . Few ancient sources are willing to discuss possible motives for the events ; those few that do , offer unconvincing rationales , are of later provenance , and are generally unreliable . At the time of the executions , it was commonly believed that the Empress Fausta was either in an illicit relationship with Crispus , or was spreading rumors to that effect . A popular myth arose , modified to allude to Hippolytus – Phaedra legend , with the suggestion that Constantine killed Crispus and Fausta for their immoralities . One source , the largely fictional " Passion of Artemius " , probably penned in the eighth century by John of Damascus , makes the legendary connection explicit . As an interpretation of the executions , the myth rests on only " the slimmest of evidence " : sources that allude to the relationship between Crispus and Fausta are late and unreliable , and the modern suggestion that Constantine ' s " godly " edicts of 326 and the irregularities of Crispus are somehow connected rests on no evidence at all . Although Constantine created his apparent heirs " Caesars " , following a pattern established by Diocletian , he gave his creations a hereditary character , alien to the tetrarchic system : Constantine ' s Caesars were to be kept in the hope of ascending to Empire , and entirely subordinated to their Augustus , as long as he was alive . Therefore , an alternative explanation for the execution of Crispus was , perhaps , Constantine ' s desire to keep a firm grip on his prospective heirs , this — and Fausta ' s desire for having her sons inheriting instead of their half - brother — being reason enough for killing Crispus ; the subsequent execution of Fausta , however , was probably meant as a reminder to her children that Constantine would not hesitate in " killing his own relatives when he felt this was necessary " . Later campaigns . Constantine considered Constantinople as his capital and permanent residence . He lived there for a good portion of his later life . He rebuilt Trajan ' s bridge across the Danube , in hopes of reconquering Dacia , a province that had been abandoned under Aurelian . In the late winter of 332 , Constantine campaigned with the Sarmatian s against the Goths . The weather and lack of food cost the Goths dearly : reportedly , nearly one hundred thousand died before they submitted to Rome . In 334 , after Sarmatian commoners had overthrown their leaders , Constantine led a campaign against the tribe . He won a victory in the war and extended his control over the region , as remains of camps and fortifications in the region indicate . Constantine resettled some Sarmatian exiles as farmers in Illyrian and Roman districts , and conscripted the rest into the army . Constantine took the title " Dacicus maximus " in 336 . In the last years of his life Constantine made plans for a campaign against Persia . In a letter written to the king of Persia , Shapur , Constantine had asserted his patronage over Persia ' s Christian subjects and urged Shapur to treat them well . The letter is undatable . In response to border raids , Constantine sent Constantius to guard the eastern frontier in 335 . In 336 , prince Narseh invaded Armenia ( a Christian kingdom since 301 ) and installed a Persian client on the throne . Constantine then resolved to campaign against Persia himself . He treated the war as a Christian crusade , calling for bishops to accompany the army and commissioning a tent in the shape of a church to follow him everywhere . Constantine planned to be baptized in the Jordan River before crossing into Persia . Persian diplomats came to Constantinople over the winter of 336 – 7 , seeking peace , but Constantine turned them away . The campaign was called off however , when Constantine fell sick in the spring of 337 . Sickness and death . Constantine had known death would soon come . Within the Church of the Holy Apostles , Constantine had secretly prepared a final resting - place for himself . It came sooner than he had expected . Soon after the Feast of Easter 337 , Constantine fell seriously ill . He left Constantinople for the hot baths near his mother ' s city of Helenopolis ( Altinova ) , on the southern shores of the Gulf of İzmit . There , in a church his mother built in honor of Lucian the Apostle , he prayed , and there he realized that he was dying . Seeking purification , he became a catechumen , and attempted a return to Constantinople , making it only as far as a suburb of Nicomedia . He summoned the bishops , and told them of his hope to be baptized in the River Jordan , where Christ was written to have been baptized . He requested the baptism right away , promising to live a more Christian life should he live through his illness . The bishops , Eusebius records , " performed the sacred ceremonies according to custom " . He chose the Arianizing bishop Eusebius of Nicomedia , bishop of the city where he lay dying , as his baptizer . In postponing his baptism , he followed one custom at the time which postponed baptism until after infancy . It has been thought that Constantine put off baptism as long as he did so as to be absolved from as much of his sin as possible . Constantine died soon after at a suburban villa called Achyron , on the last day of the fifty - day festival of Pentecost directly following Pascha ( or Easter ) , on 22 May 337 . Although Constantine ' s death follows the conclusion of the Persian campaign in Eusebius ' s account , most other sources report his death as occurring in its middle . Emperor Julian ( a nephew of Constantine ) , writing in the mid - 350s , observes that the Sassanian s escaped punishment for their ill - deeds , because Constantine died " in the middle of his preparations for war " . Similar accounts are given in the " Origo Constantini " , an anonymous document composed while Constantine was still living , and which has Constantine dying in Nicomedia ; the " Historiae abbreviatae " of Sextus Aurelius Victor , written in 361 , which has Constantine dying at an estate near Nicomedia called Achyrona while marching against the Persians ; and the " Breviarium " of Eutropius , a handbook compiled in 369 for the Emperor Valens , which has Constantine dying in a nameless state villa in Nicomedia . From these and other accounts , some have concluded that Eusebius ' s " Vita " was edited to defend Constantine ' s reputation against what Eusebius saw as a less congenial version of the campaign . Following his death , his body was transferred to Constantinople and buried in the Church of the Holy Apostles there . He was succeeded by his three sons born of Fausta , Constantine II , Constantius II and Constans . A number of relatives were killed by followers of Constantius , notably Constantine ' s nephews Dalmatius ( who held the rank of Caesar ) and Hannibalianus , presumably to eliminate possible contenders to an already complicated succession . He also had two daughters , Constantina and Helena , wife of Emperor Julian . Legacy . Although he earned his honorific of " The Great " ( " Μέγας " ) from Christian historians long after he had died , he could have claimed the title on his military achievements and victories alone . Besides reuniting the Empire under one emperor , Constantine won major victories over the Franks and Alamanni in 306 – 8 , the Franks again in 313 – 14 , the Goths in 332 and the Sarmatians in 334 . By 336 , Constantine had reoccupied most of the long - lost province of Dacia , which Aurelian had been forced to abandon in 271 . At the time of his death , he was planning a great expedition to end raids on the eastern provinces from the Persian Empire . Serving for a total of almost 31 years ( combining his years as co - ruler and sole ruler ) , he was also the longest serving emperor since Augustus and the second longest serving emperor in Roman history . In the cultural sphere Constantine contributed to the revival of the clean shaven face fashion of the Roman emperors from Augustus to Trajan , which was originally introduced among the Romans by Scipio Africanus . This new Roman imperial fashion lasted until the reign of Phocas . The Byzantine Empire considered Constantine its founder and the Holy Roman Empire reckoned him among the venerable figures of its tradition . In the later Byzantine state , it had become a great honor for an emperor to be hailed as a " new Constantine " . Ten emperors , including the last emperor of Byzantium , carried the name . Monumental Constantinian forms were used at the court of Charlemagne to suggest that he was Constantine ' s successor and equal . Constantine acquired a mythic role as a warrior against " heathens " . The motif of the Romanesque equestrian , the mounted figure in the posture of a triumphant Roman emperor , became a visual metaphor in statuary in praise of local benefactors . The name " Constantine " itself enjoyed renewed popularity in western France in the eleventh and twelfth centuries . Most Eastern Christian churches consider Constantine a saint ( Άγιος Κωνσταντίνος , Saint Constantine ) . In the Byzantine Church he was called " isapostolos " ( Ισαπόστολος Κωνσταντίνος ) — an equal of the Apostles . Niš airport is named Constantine the Great in honor of his birth in Naissus . Historiography . During his life and those of his sons , Constantine was presented as a paragon of virtue . Pagans such as Praxagoras of Athens and Libanius showered him with praise . When the last of his sons died in 361 , however , his nephew ( and son - in - law ) Julian the Apostate wrote the satire " Symposium , or the Saturnalia " , which denigrated Constantine , calling him inferior to the great pagan emperors , and given over to luxury and greed . Following Julian , Eunapius began — and Zosimus continued — a historiographic tradition that blamed Constantine for weakening the Empire through his indulgence to the Christians . In medieval times , when the Roman Catholic Church was dominant , Catholic historians presented Constantine as an ideal ruler , the standard against which any king or emperor could be measured . The Renaissance rediscovery of anti - Constantinian sources prompted a re - evaluation of Constantine ' s career . The German humanist Johann Löwenklau , discoverer of Zosimus ' writings , published a Latin translation thereof in 1576 . In its preface , he argued that Zosimus ' picture of Constantine was superior to that offered by Eusebius and the Church historians , and damned Constantine as a tyrant . Cardinal Caesar Baronius , a man of the Counter - Reformation , criticized Zosimus , favoring Eusebius ' account of the Constantinian era . Baronius ' " Life of Constantine " ( 1588 ) presents Constantine as the model of a Christian prince . For his " History of the Decline and Fall of the Roman Empire " ( 1776 – 89 ) , Edward Gibbon , aiming to unite the two extremes of Constantinian scholarship , offered a portrait of Constantine built on the contrasted narratives of Eusebius and Zosimus . In a form that parallels his account of the empire ' s decline , Gibbon presents a noble war hero corrupted by Christian influences , who transforms into an Oriental despot in his old age : " a hero . . . degenerating into a cruel and dissolute monarch " . Modern interpretations of Constantine ' s rule begin with Jacob Burckhardt ' s " The Age of Constantine the Great " ( 1853 , rev . 1880 ) . Burckhardt ' s Constantine is a scheming secularist , a politician who manipulates all parties in a quest to secure his own power . Henri Grégoire , writing in the 1930s , followed Burckhardt ' s evaluation of Constantine . For Grégoire , Constantine developed an interest in Christianity only after witnessing its political usefulness . Grégoire was skeptical of the authenticity of Eusebius ' " Vita " , and postulated a pseudo - Eusebius to assume responsibility for the vision and conversion narratives of that work . Otto Seeck , in " Geschichte des Untergangs der antiken Welt " ( 1920 – 23 ) , and André Piganiol , in " L ' empereur Constantin " ( 1932 ) , wrote against this historiographic tradition . Seeck presented Constantine as a sincere war hero , whose ambiguities were the product of his own naïve inconsistency . Piganiol ' s Constantine is a philosophical monotheist , a child of his era ' s religious syncretism . Related histories by A . H . M . Jones ( " Constantine and the Conversion of Europe " ( 1949 ) ) and Ramsay MacMullen ( " Constantine " ( 1969 ) ) gave portraits of a less visionary , and more impulsive , Constantine . These later accounts were more willing to present Constantine as a genuine convert to Christianity . Beginning with Norman H . Baynes ' " Constantine the Great and the Christian Church " ( 1929 ) and reinforced by Andreas Alföldi ' s " The Conversion of Constantine and Pagan Rome " ( 1948 ) , a historiographic tradition developed which presented Constantine as a committed Christian . T . D . Barnes ' s seminal " Constantine and Eusebius " ( 1981 ) represents the culmination of this trend . Barnes ' Constantine experienced a radical conversion , which drove him on a personal crusade to convert his empire . Charles Matson Odahl ' s recent " Constantine and the Christian Empire " ( 2004 ) takes much the same tack . In spite of Barnes ' work , arguments over the strength and depth of Constantine ' s religious conversion continue . Certain themes in this school reached new extremes in T . G . Elliott ' s " The Christianity of Constantine the Great " ( 1996 ) , which presented Constantine as a committed Christian from early childhood . A similar view of Constantine is held in Paul Veyne ' s recent ( 2007 ) work , " Quand notre monde est devenu chrétien " , which does not speculate on the origins of Constantine ' s Christian motivation , but presents him , in his role as Emperor , as a religious revolutionary who fervently believed himself meant " to play a providential role in the millenary economy of the salvation of humanity " . Donation of Constantine . Latin Rite Catholics considered it inappropriate that Constantine was baptized only on his death - bed and by an unorthodox bishop , as it undermined the authority of the Papacy . Hence , by the early fourth century , a legend had emerged that Pope Sylvester I ( 314 – 35 ) had cured the pagan emperor from leprosy . According to this legend , Constantine was soon baptized , and began the construction of a church in the Lateran Palace . In the eighth century , most likely during the pontificate of Stephen II ( 752 – 7 ) , a document called the Donation of Constantine first appeared , in which the freshly converted Constantine hands the temporal rule over " the city of Rome and all the provinces , districts , and cities of Italy and the Western regions " to Sylvester and his successors . In the High Middle Ages , this document was used and accepted as the basis for the Pope ' s temporal power , though it was denounced as a forgery by Emperor Otto III and lamented as the root of papal worldliness by the poet Dante Alighieri . The 15th century philologist Lorenzo Valla proved the document was indeed a forgery . Geoffrey of Monmouth ' s " Historia " . Because of his fame and his being proclaimed Emperor in the territory of Roman Britain , later Britons regarded Constantine as a king of their own people . In the 12th century Henry of Huntingdon included a passage in his " Historia Anglorum " that Constantine ' s mother Helena was a Briton , the daughter of King Cole of Colchester . Geoffrey of Monmouth expanded this story in his highly fictionalized " Historia Regum Britanniae " , an account of the supposed Kings of Britain from their Trojan origins to the Anglo - Saxon invasion . According to Geoffrey , Cole was King of the Britons when Constantius , here a senator , came to Britain . Afraid of the Romans , Cole submitted to Roman law so long as he retained his kingship . However , he died only a month later , and Constantius took the throne himself , marrying Cole ' s daughter Helena . They had their son Constantine , who succeeded his father as King of Britain before becoming Roman Emperor . Historically , this series of events is extremely improbable . Constantius had already left Helena by the time he left for Britain . Additionally , no earlier source mentions that Helena was born in Britain , let alone that she was a princess . Henry ' s source for the story is unknown , though it may have been a lost hagiography of Helena . Constantine in popular culture . Constantine was played by Cornel Wilde in the 1962 film " Constantine and the Cross " ( U . S . title ) / " Constantine the Great " ( U . K . title ) . " Constantine : The Miracle of the Flaming Cross " is a romanticised , novelised account of Constantine ' s life written by American author Frank G . Slaughter and published in 1965 . It largely drew on Edward Gibbon ' s history of the Roman Empire as well as Eusebius of Caesarea ' s contemporary account , as indicated in the afterword of the original edition . Citations . Essays from " The Cambridge Companion to the Age of Constantine " are marked with a " ( CC ) " .