Roman emperor - wikipedia Roman emperor Not to be confused with Holy Roman Emperor. For the ruler of the Roman Kingdom in the archaic period, see Kings of Rome. For the dual chief magistrates during the Roman Republic, see Roman consul. For the Roman emperors, see List of Roman emperors. Emperor of the Roman Empire Imperator Imperii Romani Imperial Vexillum of the Emperor First to reign Augustus 16 January 27 BC -- 19 August AD 14 Details Style Imperator, Augustus, Caesar, Princeps, Dominus Noster, Autokrator or Basileus ( depending on period ) First monarch Augustus Last monarch Theodosius I ( Unified or Classical ), Julius Nepos ( Western ), Constantine XI ( Eastern ) Formation 16 January 27 BC Abolition 17 January 395 AD ( Unified or Classical ), 22 June 480 AD ( Western ), 29 May 1453 AD ( Eastern ) Appointer Roman Military and / or Roman Senate ( traditionally ) Pretender ( s ) none The Roman Emperor was the ruler of the Roman Empire during the imperial period ( starting in 27 BC ). The emperors used a variety of different titles throughout history. Often when a given Roman is described as becoming `` emperor '' in English, it reflects his taking of the title Augustus or Caesar. Another title often used was imperator, originally a military honorific. Early Emperors also used the title princeps ( first citizen ). Emperors frequently amassed republican titles, notably Princeps senatus, Consul and Pontifex Maximus. The legitimacy of an emperor 's rule depended on his control of the army and recognition by the Senate ; an emperor would normally be proclaimed by his troops, or invested with imperial titles by the Senate, or both. The first emperors reigned alone ; later emperors would sometimes rule with co-Emperors and divide administration of the Empire between them. The Romans considered the office of emperor to be distinct from that of a king. The first emperor, Augustus, resolutely refused recognition as a monarch. Although Augustus could claim that his power was authentically republican, his successor, Tiberius, could not convincingly make the same claim. Nonetheless, for the first three hundred years of Roman Emperors, from Augustus until Diocletian, a great effort was made to emphasize that the Emperors were the leaders of a Republic. From Diocletian onwards, emperors ruled in an openly monarchic style and did not preserve the nominal principle of a republic, but the contrast with `` kings '' was maintained : although the imperial succession was generally hereditary, it was only hereditary if there was a suitable candidate acceptable to the army and the bureaucracy, so the principle of automatic inheritance was not adopted. Elements of the Republican institutional framework ( senate, consuls, and magistrates ) were preserved until the very end of the Western Empire. The Eastern ( Byzantine ) emperors ultimately adopted the title of `` Basileus '' ( βασιλεύς ), which had meant king in Greek, but became a title reserved solely for the Roman Emperor and the ruler of the Sasanian Empire. Other kings were then referred to as rēgas. In addition to their pontifical office, some emperors were given divine status after death. With the eventual hegemony of Christianity, the emperor came to be seen as God 's chosen ruler, as well as a special protector and leader of the Christian Church on Earth, although in practice an emperor 's authority on Church matters was subject to challenge. The Western Roman Empire collapsed in the late 5th century. Romulus Augustulus is often considered to be the last emperor of the west after his forced abdication in 476, although Julius Nepos maintained a claim to the title until his death in 480. Meanwhile, in the east, emperors continued to rule from Constantinople ( `` New Rome '' ) ; these are referred to in modern scholarship as `` Byzantine emperor '' but they used no such title and called themselves `` Emperor of the Romans '' ( βασιλεύς Ῥωμαίων ). Constantine XI Palaiologos was the last Byzantine Roman Emperor in Constantinople, dying in the Fall of Constantinople to the Ottomans in 1453. Due to the cultural rupture of the Turkish conquest, most western historians treat Constantine XI as the last meaningful claimant to the title Roman Emperor, although from 1453 Ottoman rulers were titled `` Caesar of Rome '' ( Turkish : Kayser - i Rum ) until the Ottoman Empire ended in 1922. A Byzantine group of claimant Roman Emperors existed in the Empire of Trebizond until its conquest by the Ottomans in 1461. In western Europe the title of Roman Emperor was revived by Germanic rulers, the `` Holy Roman Emperors '', in 800, and was used until 1806. Contents 1 Background and first Roman emperor 2 Classical period 2.1 Imperator 2.2 Princeps 2.3 Evolution in Late Antiquity 3 Titles and positions 3.1 Powers 4 Lineages and epochs 4.1 Principate 4.2 Crisis of the Third Century 4.3 Dominate 4.4 Late empire 5 Post-classical assertions to the title 5.1 Survival of the Roman Empire in the East 5.2 Last Roman emperor 5.3 New Western lineage 6 See also 7 References 8 Sources 9 Further reading 10 External links Background and first Roman emperor Statue of Augustus, c. 30 BC -- 20 BC ; this statue is located in the Louvre Modern historians conventionally regard Augustus as the first Emperor whereas Julius Caesar is considered the last dictator of the Roman Republic, a view having its origins in the Roman writers Plutarch, Tacitus and Cassius Dio. However, the majority of Roman writers, including Josephus, Pliny the Younger, Suetonius and Appian, as well as most of the ordinary people of the Empire, thought of Julius Caesar as the first Emperor. At the end of the Roman Republic no new, and certainly no single, title indicated the individual who held supreme power. Insofar as emperor could be seen as the English translation of imperator, then Julius Caesar had been an emperor, like several Roman generals before him. Instead, by the end of the civil wars in which Julius Caesar had led his armies, it became clear that there was certainly no consensus to return to the old - style monarchy, but that the period when several officials, bestowed with equal power by the senate, would fight one another had come to an end. Julius Caesar, and then Augustus after him, accumulated offices and titles of the highest importance in the Republic, making the power attached to those offices permanent, and preventing anyone with similar aspirations from accumulating or maintaining power for themselves. However, Julius Caesar, unlike those after him, did so without the Senate 's vote and approval. Julius Caesar held the Republican offices of consul four times and dictator five times, was appointed dictator in perpetuity ( dictator perpetuo ) in 45 BC and had been `` pontifex maximus '' for a long period. He gained these positions by senatorial consent. By the time of his assassination, he was the most powerful man in the Roman world. In his will, Caesar appointed his adopted son Octavian as his heir. On Caesar 's death, Octavian inherited his adoptive father 's property and lineage, the loyalty of most of his allies and -- again through a formal process of senatorial consent -- an increasing number of the titles and offices that had accrued to Caesar. A decade after Caesar 's death, Octavian 's victory over his erstwhile ally Mark Antony at Actium put an end to any effective opposition and confirmed Octavian 's supremacy. In 27 BC, Octavian appeared before the Senate and offered to retire from active politics and government ; the Senate not only requested he remain, but increased his powers and made them lifelong, awarding him the title of Augustus ( the elevated or divine one, somewhat less than a god but approaching divinity ). Augustus stayed in office until his death ; the sheer breadth of his superior powers as princeps and permanent imperator of Rome 's armies guaranteed the peaceful continuation of what nominally remained a republic. His `` restoration '' of powers to the Senate and the people of Rome was a demonstration of his auctoritas and pious respect for tradition. Some later historians such as Tacitus would say that even at Augustus ' death, the true restoration of the Republic might have been possible. Instead, Augustus actively prepared his adopted son Tiberius to be his successor and pleaded his case to the Senate for inheritance on merit. The Senate disputed the issue but eventually confirmed Tiberius as princeps. Once in power, Tiberius took considerable pains to observe the forms and day - to - day substance of republican government. Classical period Ancient Rome This article is part of a series on the politics and government of ancient Rome Periods Roman Kingdom 753 -- 509 BC Roman Republic 509 -- 27 BC Roman Empire 27 BC -- AD 395 Principate Dominate Western AD 395 -- 476 Eastern AD 395 -- 1453 Empire of Trebizond AD 1204 -- 1461 Timeline Roman Constitution Constitution of the Kingdom Constitution of the Republic Constitution of the Empire Constitution of the Late Empire Senate Legislative assemblies Executive magistrates Ordinary magistrates Consul Praetor Quaestor Promagistrate Aedile Tribune Censor Governor Extraordinary magistrates Dictator Magister equitum Consular tribune Rex Triumviri Decemviri Titles and honours Emperor Legatus Dux Officium Praefectus Vicarius Vigintisexviri Lictor Magister militum Imperator Princeps senatus Pontifex maximus Augustus Caesar Tetrarch Precedent and law Roman law Ius Imperium Mos maiorum Collegiality Auctoritas Roman citizenship Cursus honorum Senatus consultum Senatus consultum ultimum Assemblies Centuriate Curiate Plebeian Tribal Other countries Atlas Rome had no single constitutional office, title or rank exactly equivalent to the English title `` Roman emperor ''. Romans of the Imperial era used several titles to denote their emperors, and all were associated with the pre-Imperial, Republican era. The emperor 's legal authority derived from an extraordinary concentration of individual powers and offices that were extant in the Republic rather than from a new political office ; emperors were regularly elected to the offices of consul and censor. Among their permanent privileges were the traditional Republican title of princeps senatus ( leader of the Senate ) and the religious office of pontifex maximus ( chief priest of the College of Pontiffs ). Every emperor held the latter office and title until Gratian surrendered it in AD 382 to Pope Siricius ; it eventually became an auxiliary honor of the Bishop of Rome. These titles and offices conferred great personal prestige ( dignitas ) but the basis of an emperor 's powers derived from his auctoritas : this assumed his greater powers of command ( imperium maius ) and tribunician power ( tribunicia potestas ) as personal qualities, separate from his public office. As a result, he formally outranked provincial governors and ordinary magistrates. He had the right to enact or revoke sentences of capital punishment, was owed the obedience of private citizens ( privati ) and by the terms of the ius auxiliandi could save any plebeian from any patrician magistrate 's decision. He could veto any act or proposal of any magistrate, including the tribunes of the people ( ius intercedendi or ius intercessionis ). His person was held to be sacrosanct. Roman magistrates on official business were expected to wear the form of toga associated with their office ; different togas were worn by different ranks ; senior magistrates had the right to togas bordered with purple. A triumphal imperator of the Republic had the right to wear the toga picta ( of solid purple, richly embroidered ) for the duration of the triumphal rite. During the Late Republic, the most powerful had this right extended. Pompey and Caesar are both thought to have worn the triumphal toga and other triumphal dress at public functions. Later emperors were distinguished by wearing togae purpurae, purple togas ; hence the phrase `` to don the purple '' for the assumption of imperial dignity. The titles customarily associated with the imperial dignity are imperator ( `` commander '' ), which emphasizes the emperor 's military supremacy and is the source of the English word emperor ; Caesar, which was originally a name but came to be used for the designated heir ( as Nobilissimus Caesar, `` Most Noble Caesar '' ) and was retained upon accession. The ruling emperor 's title was the descriptive Augustus ( `` majestic '' or `` venerable '', which had tinges of the divine ), which was adopted upon accession. In Greek, these three titles were rendered as autokratōr ( `` Αὐτοκράτωρ '' ), kaisar ( `` Καίσαρ '' ), and augoustos ( `` Αὔγουστος '' ) or sebastos ( `` Σεβαστός '' ) respectively. In Diocletian 's Tetrarchy, the traditional seniorities were maintained : `` Augustus '' was reserved for the two senior emperors and `` Caesar '' for the two junior emperors -- each delegated a share of power and responsibility but each an emperor - in - waiting, should anything befall his senior. As princeps senatus ( lit., `` first man of the senate '' ), the emperor could receive foreign embassies to Rome ; some emperors ( such as Tiberius ) are known to have delegated this task to the Senate. In modern terms these early emperors would tend to be identified as chiefs of state. The office of princeps senatus, however, was not a magistracy and did not entail imperium. At some points in the Empire 's history, the emperor 's power was nominal ; powerful praetorian prefects, masters of the soldiers and on a few occasions, other members of the Imperial household including Imperial mothers and grandmothers were the true source of power. Imperator Main article : Imperator The title imperator dates back to the Roman Republic, when a victorious commander could be hailed as imperator in the field by his troops. The Senate could then award or withhold the extraordinary honour of a triumph ; the triumphal commander retained the title until the end of his magistracy. In Roman tradition, the first triumph was that of Romulus, but the first attested recipient of the title imperator in a triumphal context is Aemilius Paulus in 189 BC. It was a title held with great pride : Pompey was hailed imperator more than once, as was Sulla, but it was Julius Caesar who first used it permanently -- according to Dio, this was a singular and excessive form of flattery granted by the Senate, passed to Caesar 's adopted heir along with his name and virtually synonymous with it. In 38 BC Agrippa refused a triumph for his victories under Octavian 's command, and this precedent established the rule that the princeps should assume both the salutation and title of imperator. It seems that from then on Octavian ( later the first emperor Augustus ) used imperator as a first name ( praenomen ) : Imperator Caesar not Caesar imperator. From this the title came to denote the supreme power and was commonly used in that sense. Otho was the first to imitate Augustus, but only with Vespasian did imperator ( emperor ) become the official title by which the ruler of the Roman Empire was known. Princeps Main articles : Principate and Roman Emperor ( Principate ) The word princeps ( plural principes ), meaning `` first '', was a republican term used to denote the leading citizen ( s ) of the state. It was a purely honorific title with no attached duties or powers. It was the title most preferred by Caesar Augustus as its use implies only primacy, as opposed to another of his titles, imperator, which implies dominance. Princeps, because of its republican connotation, was most commonly used to refer to the emperor in Latin ( although the emperor 's actual constitutional position was essentially `` pontifex maximus with tribunician power and imperium superseding all others '' ) as it was in keeping with the façade of the restored Republic ; the Greek word basileus ( `` king '' ) was modified to be synonymous with emperor ( and primarily came into favour after the reign of Heraclius ) as the Greeks had no republican sensibility and openly viewed the emperor as a monarch. In the era of Diocletian and beyond, princeps fell into disuse and was replaced with dominus ( `` lord '' ) ; later emperors used the formula Imperator Caesar NN. Pius Felix ( Invictus ) Augustus : NN representing the individual 's personal name ; Pius Felix meaning `` Pious and Blest '' ; and Invictus meaning `` undefeated ''. The use of princeps and dominus broadly symbolise the differences in the empire 's government, giving rise to the era designations `` Principate '' and `` Dominate ''. Evolution in late antiquity In 293, following the Crisis of the Third Century which had severely damaged Imperial administration, Emperor Diocletian enacted sweeping reforms that washed away many of the vestiges and façades of republicanism which had characterized the Augustan order in favor of a more frank autocracy. As a result, historians distinguish the Augustan period as the principate and the period from Diocletian to the 7th century reforms of Emperor Heraclius as the dominate ( from the Latin for `` lord ''. ) Reaching back to the oldest traditions of job - sharing in the republic, however, Diocletian established at the top of this new structure the Tetrarchy ( `` rule of four '' ) in an attempt to provide for smoother succession and greater continuity of government. Under the Tetrarchy, Diocletian set in place a system of co-emperors, styled `` Augustus '', and junior emperors, styled `` Caesar ''. When a co-emperor retired ( as Diocletian and his co-emperor Maximian did in 305 ) or died, a junior `` Caesar '' would succeed him and the co-emperors would appoint new Caesars as needed. The four members of the Imperial college ( as historians call the arrangement ) shared military and administrative challenges by each being assigned specific geographic areas of the empire. From this innovation, often but not consistently repeated over the next 187 years, comes the notion of an east - west partition of the empire that became popular with historians long after the practice had stopped. The two halves of empire, while often run as de facto separate entities day - to - day, were always considered and seen, legally and politically, as separate administrative divisions of a single, insoluble imperium by the Romans of the time. The final period of co-emperorship began in 395, when Emperor Theodosius I 's sons Arcadius and Honorius succeeded as co-emperors. Eighty - five years later, following Germanic migrations which had reduced the empire 's effective control across Brittania, Gaul and Hispania and a series of military coup d'état which drove Emperor Nepos out of Italy, the idea of dividing the position of emperor was formally abolished by Emperor Zeno ( 480 ). The Roman Empire survived in the east until 1453, but the marginalization of the former heartland of Italy to the empire had a profound cultural impact on the empire and the position of emperor. In 620, the official language was changed from Latin to Greek. The Greek - speaking inhabitants were Romaioi ( Ῥωμαῖοι ), and were still considered Romans by themselves and the populations of Eastern Europe, the Near East, India, and China. But many in Western Europe began to refer to the political entity as the `` Greek Empire ''. The evolution of the church in the no - longer imperial city of Rome and the church in the now supreme Constantinople began to follow divergent paths, culminating in the schism between the Roman Catholic and Eastern Orthodox faiths. The position of emperor was increasingly influenced by Near Eastern concepts of kingship. Starting with Emperor Heraclius, Roman emperors styled themselves `` King of Kings '' ( from the imperial Persian Shahanshah ) from 627 and `` Basileus '' ( from the title used by Alexander the Great ) from 629. The later period of the empire is today called the Byzantine Empire as a matter of scholarly convention. Titles and positions Although these are the most common offices, titles, and positions, not all Roman emperors used them, nor were all of them used at the same time in history. The consular and censorial offices especially were not an integral part of the Imperial dignity, and were usually held by persons other than the reigning emperor. Augustus : ( also `` Αὔγουστος '' or `` Σεβαστός '' ), `` Majestic '' or `` Venerable '' ; an honorific cognomen exclusive to the emperor Autokrator : ( Αὐτοκράτωρ, Autokratōr ), ( lit. `` Self - ruler '' ) ; Greek title equivalent to imperator or commander - in - chief Basileus : ( Βασιλεύς ), Greek for king, popularly used in the east to refer to the emperor ; a formal title of the Roman emperor beginning with Heraclius Caesar : ( also `` Καίσαρ '' ), `` Caesar '' ; initially the cognomen of Julius Caesar, it was transformed into a title ; an honorific name later used to identify an emperor - designate Censor : a Republican office held jointly by two former consuls every five years for the purpose of conducting the lustrum that determined the role of citizens ; the censor could audit all other magistrates and all state finances Consul : the highest magistracy of the Roman Republic with a one - year term and one coequal officeholder ; the consul was the head of state within Rome. The last emperor to be bestowed the title by the Senate was Constans II, who was also the last emperor to visit Rome. Dominus ( `` Lord '' or `` Master '' ) : an honorific title mainly associated with the Dominate Dominus Noster ( `` Our Lord '' ) : an honorific title ; the praenomen of later emperors. Imperator ( `` Commander '' or `` Commander - in - Chief '' ) : a victory title taken on accession to the purple and after a major military victory Imperator Destinatus ( `` Destined to be Emperor '' ) : heir apparent, used by Septimius Severus for Caracalla Invictus ( `` Unconquered '' ), an honorific title. Nobilissimus : ( Nωβελίσσιμος, Nōbelissimos ), ( `` Most Noble '' ), one of the highest imperial titles held by the emperor Pater Patriae ( `` Father of the Fatherland '' ) : an honorific title Perpetuus ( `` Universal '' ) : an honorific title of later emperors Pius Felix ( `` Pious and Blessed '' ) : an honorific title Pontifex Maximus ( `` Supreme Pontiff '' or `` Chief Priest '' ) : in the Republican era, the Pontifex Maximus was the head of the College of Pontiffs, the religious body that oversaw the ancestral public religion of the Romans ; Julius Caesar had become Pontifex Maximus before he was elected consul, and the precedent set by his heir Augustus in consolidating supreme authority through this religious office was in general followed by his successors until the empire came under Christian rule Princeps ( `` First Citizen '' or `` Leading Citizen '' ) : an honorific title denoting the status of the emperor as first among equals, associated mainly with the Principate Princeps Iuventutis : ( `` Prince of Youth '' ), an honorific title awarded to a presumptive emperor - designate Princeps Senatus : ( `` First Man of the Senate '' ), a Republican office with a five - year term Sebastos : ( Σεβαστός ), ( `` Venerable '' ) ; the Greek rendition of the imperial title Augustus Sebastokrator : ( Σεβαστοκράτωρ, Sebastokratōr ), ( `` Venerable Ruler ) ; a senior court title from the compound words `` sebastos '' ( `` venerable '', the Greek equivalent of the Latin Augustus ) and `` kratōr '' ( `` ruler '', the same element as is found in `` autokratōr '', `` emperor '' ) Tribunicia Potestas : ( `` Tribunician Power '' ) ; the powers of a tribune of the people, including sacrosanctity and inviolability of his person, and the veto over any decision by any other magistrate, assembly, or the Senate ( the emperor could not be a `` tribune '' because a tribune was a plebeian by definition, therefore the emperor had all the powers of a tribune without actually being one ) Powers When Augustus established the Princeps, he turned down supreme authority in exchange for a collection of various powers and offices, which in itself was a demonstration of his auctoritas ( `` authority '' ). As holding princeps senatus, the emperor declared the opening and closure of each Senate session, declared the Senate 's agenda, imposed rules and regulation for the Senate to follow, and met with foreign ambassadors in the name of the Senate. Being pontifex maximus made the emperor the chief administrator of religious affairs, granting him the power to conduct all religious ceremonies, consecrate temples, control the Roman calendar ( adding or removing days as needed ), appoint the vestal virgins and some flamens, lead the Collegium Pontificum, and summarize the dogma of the Roman religion. While these powers granted the emperor a great deal of personal pride and influence, they did not include legal authority. In 23 BC, Augustus gave the emperorship its legal power. The first was Tribunicia Potestas, or the powers of the tribune of the plebs without actually holding the office ( which would have been impossible, since a tribune was by definition a plebeian, whereas Augustus, although born into a plebeian family, had become a patrician when he was adopted into the gens Julia ). This endowed the emperor with inviolability ( sacrosanctity ) of his person, and the ability to pardon any civilian for any act, criminal or otherwise. By holding the powers of the tribune, the emperor could prosecute anyone who interfered with the performance of his duties. The emperor 's tribuneship granted him the right to convene the Senate at his will and lay proposals before it, as well as the ability to veto any act or proposal by any magistrate, including the actual tribune of the plebeians. Also, as holder of the tribune 's power, the emperor would convoke the Council of the People, lay legislation before it, and served as the council 's president. But his tribuneship only granted him power within Rome itself. He would need another power to veto the act of governors and that of the consuls while in the provinces. To solve this problem, Augustus managed to have the emperor be given the right to hold two types of imperium. The first being consular imperium while he was in Rome, and imperium maius outside of Rome. While inside the walls of Rome, the reigning consuls and the emperor held equal authority, each being able to veto each other 's proposals and acts, with the emperor holding all of the consul 's powers. But outside of Rome, the emperor outranked the consuls and could veto them without the same effects on himself. Imperium Maius also granted the emperor authority over all the provincial governors, making him the ultimate authority in provincial matters and gave him the supreme command of all of Rome 's legions. With Imperium Maius, the emperor was also granted the power to appoint governors of imperial provinces without the interference of the Senate. Also, Imperium Maius granted the emperor the right to veto the governors of the provinces and even the reigning consul while in the provinces. Lineages and epochs Principate Main article : Roman Emperor ( Principate ) The nature of the imperial office and the Principate was established under Julius Caesar 's heir and posthumously adopted son, Caesar Augustus, and his own heirs, the descendants of his wife Livia from her first marriage to a scion of the distinguished Claudian clan. This Julio - Claudian dynasty came to an end when the Emperor Nero -- a great - great - grandson of Augustus through his daughter and of Livia through her son -- was deposed in 68. Nero was followed by a succession of usurpers throughout 69, commonly called the `` Year of the Four Emperors ''. The last of these, Vespasian, established his own Flavian dynasty. Nerva, who replaced the last Flavian emperor, Vespasian 's son Domitian, in 96, was elderly and childless, and chose therefore to adopt an heir, Trajan, from outside his family. When Trajan acceded to the purple he chose to follow his predecessor 's example, adopting Hadrian as his own heir, and the practice then became the customary manner of imperial succession for the next century, producing the `` Five Good Emperors '' and the Empire 's period of greatest stability. The last of the Good Emperors, Marcus Aurelius, chose his natural son Commodus as his successor rather than adopting an heir. Commodus 's misrule led to his murder on 31 December 192, following which a brief period of instability quickly gave way to Septimius Severus, who established the Severan dynasty which, except for an interruption in 217 -- 218 when Macrinus was emperor, held the purple until 235. Crisis of the Third century Main article : Roman Emperor ( Crisis of the Third Century ) The accession of Maximinus Thrax marks both the close and the opening of an era. It was one of the last attempts by the increasingly impotent Roman Senate to influence the succession. Yet it was the second time that a man had achieved the purple while owing his advancement purely to his military career ; both Vespasian and Septimius Severus had come from noble or middle - class families, while Thrax was born a commoner. He never visited the city of Rome during his reign, which marks the beginning of a series of `` barracks emperors '' who came from the army. Between 235 and 285 over a dozen emperors achieved the purple, but only Valerian and Carus managed to secure their own sons ' succession to the throne ; both dynasties died out within two generations. Dominate Main article : Roman Emperor ( Dominate ) The accession on 20 November 284, of Diocletian, the lower - class, Greek - speaking Dalmatian commander of Carus 's and Numerian 's household cavalry ( protectores domestici ), marked major innovations in Rome 's government and constitutional theory. Diocletian, a traditionalist and religious conservative, attempted to secure efficient, stable government and a peaceful succession with the establishment of the Tetrarchy. The empire was divided into East and West, each ruled by an Augustus assisted by a Caesar as emperor - in - waiting. These divisions were further subdivided into new or reformed provinces, administered by a complex, hierarchic bureaucracy of unprecedented size and scope. Diocletian 's own court was based at Nicomedia. His co-Augustus, Maximian, was based at Mediolanum ( modern Milan ). Their courts were peripatetic, and Imperial progressions through the provinces made much use of the impressive, theatrical adventus, or `` Imperial arrival '' ceremony, which employed an elaborate choreography of etiquette to emphasise the emperor 's elevation above other mortals. Hyperinflation of imperial honours and titles served to distinguish the Augusti from their Caesares, and Diocletian, as senior Augustus, from his colleague Maximian. The senior Augustus in particular was made a separate and unique being, accessible only through those closest to him. The overall unity of the Empire still required the highest investiture of power and status in one man. The Tetrarchy ultimately degenerated into civil war, but the eventual victor, Constantine the Great, restored Diocletian 's division of Empire into East and West. He kept the East for himself and founded his city of Constantinople as its new capital. Constantine 's own dynasty was also soon swallowed up in civil war and court intrigue until it was replaced, briefly, by Julian the Apostate 's general Jovian and then, more permanently, by Valentinian I and the dynasty he founded in 364. Though a soldier from a low middle - class background, Valentinian was made emperor by a conclave of senior generals and civil officials. Late Empire Main article : Roman Emperor ( Late Empire ) Theodosius I acceded to the purple in the East in 379 and in the West in 394. He outlawed paganism and made Christianity the Empire 's official religion. He was the last emperor to rule over a united Roman Empire ; the distribution of the East to his son Arcadius and the West to his son Honorius after his death in 395 represented a permanent division. In the West, the office of emperor soon degenerated into being little more than a puppet of a succession of Germanic tribal kings, until finally the Heruli Odoacer simply overthrew the child - emperor Romulus Augustulus in 476, shipped the imperial regalia to the Emperor Zeno in Constantinople and became King of Italy. Though during his own lifetime Odoacer maintained the legal fiction that he was actually ruling Italy as the viceroy of Zeno, historians mark 476 as the traditional date of the fall of the Roman Empire in the West. Large parts of Italy ( Sicily, the south part of the peninsula, Ravenna, Venice etc. ), however, remained under actual imperial rule from Constantinople for centuries, with imperial control slipping or becoming nominal only as late as the 11th century. In the East, the Empire continued until the fall of Constantinople to the Ottoman Turks in 1453. Although known as the Byzantine Empire by contemporary historians, the Empire was simply known as the Roman Empire to its citizens and neighboring countries. Post-classical assertions to the title Survival of the Roman Empire in the East Imaginary portrait of Constantine XI, the last Roman emperor of the Eastern Roman empire ( until 1453 ). The line of Roman emperors in the Eastern Roman Empire continued unbroken at Constantinople until the capture of Constantinople in 1204 by the Fourth Crusade. In the wake of this action, four lines of Emperors emerged, each claiming to be the legal successor : the Empire of Thessalonica, evolving from the Despotate of Epirus, which was reduced to impotence when its founder Theodore Komnenos Doukas was defeated, captured and blinded by the Bulgarian Emperor Ivan Asen III ; the Latin Empire, which came to an end when the Empire of Nicaea recovered Constantinople in 1261 ; the Empire of Trebizond, whose importance declined over the 13th century, and whose claims were simply ignored ; and the Empire of Nicaea, whose claims based on kinship with the previous emperors, control of the Patriarch of Constantinople, and possession of Constantinople through military prowess, prevailed. The successors of the emperors of Nicaea continued until the fall of Constantinople in 1453 under Constantine XI Palaiologos. These emperors eventually normalized the imperial dignity into the modern conception of an emperor, incorporated it into the constitutions of the state, and adopted the aforementioned title Basileus kai autokratōr Rhomaiōn ( `` Emperor and Autocrat of the Romans '' ). They had also ceased to use Latin as the language of state after Emperor Heraclius ( d. 641 AD ). Historians have customarily treated the state of these later Eastern emperors under the name `` Byzantine Empire ''. It is important to note, however, that the adjective Byzantine, although historically used by Eastern Roman authors in a metonymic sense, was never an official term. Last Roman emperor Main article : Constantine XI Palaiologos Constantine XI Palaiologos was the last reigning Roman emperor. A member of the Palaiologos dynasty, he ruled the remnant of the Eastern Roman Empire from 1449 until his death in 1453 defending its capital Constantinople. He was born in Mystra as the eighth of ten children of Manuel II Palaiologos and Helena Dragaš, the daughter of the Serbian prince Constantine Dragaš of Kumanovo. He spent most of his childhood in Constantinople under the supervision of his parents. During the absence of his older brother in Italy, Constantine was regent in Constantinople from 1437 -- 40. Before the beginning of the siege, Mehmed the Conqueror made an offer to Constantine XI. In exchange for the surrender of Constantinople, the emperor 's life would be spared and he would continue to rule in Mystra. Constantine refused this offer. Instead he led the defense of the city and took an active part in the fighting along the land walls. At the same time, he used his diplomatic skills to maintain the necessary unity between the Genovese, Venetian, and Byzantine troops. As the city fell on May 29, 1453, Constantine is said to have remarked : `` The city is fallen but I am alive. '' Realizing that the end had come, he reportedly discarded his purple cloak and led his remaining soldiers into a final charge, in which he was killed. With his death, Roman imperial succession came to an end, almost 1500 years after Augustus. After the fall of Constantinople, Thomas Palaiologos, brother of Constantine XI, was elected emperor and tried to organize the remaining forces. His rule came to an end after the fall of the last major Byzantine city, Corinth. He then moved in Italy and continued to be recognized as Eastern emperor by the Christian powers. His son Andreas Palaiologos continued claims on the Byzantine throne until he sold the title to Ferdinand of Aragon and Isabella of Castile, the grandparents of Holy Roman Emperor Charles V. New Western lineage Charles V was the last emperor of the Holy Roman Empire to receive a papal coronation ( until abdication in 1556 ). The concept of the Roman Empire was renewed in the West with the coronation of the king of the Franks, Charlemagne ( Charles the Great ), as Roman emperor by the Pope on Christmas Day, 800. This coronation had its roots in the decline of influence of the Pope in the affairs of the Byzantine Empire at the same time the Byzantine Empire declined in influence over politics in the West. The Pope saw no advantage to be derived from working with the Byzantine Empire, but as George Ostrogorsky points out, `` an alliance with the famous conqueror of the Lombards, on the other hand... promised much ''. The immediate response of the Eastern Roman Emperor was not welcoming. `` At that time it was axiomatic that there could be only one Empire as there could be only one church '', writes Ostrogorsky. `` The coronation of Charles the Great violated all traditional ideas and struck a hard blow at Byzantine interests, for hitherto Byzantium, the new Rome, had unquestionably been regarded as the sole Empire which had taken over the inheritance of the old Roman imperium. Conscious of its imperial rights, Byzantium could only consider the elevation of Charles the Great to be an act of usurpation. '' Nikephoros I chose to ignore Charlemagne 's claim to the imperial title, clearly recognizing the implications of this act. According to Ostrogorsky, `` he even went so far as to refuse the Patriarch Nicephorus permission to dispatch the customary synodica to the Pope. '' Meanwhile, Charlemagne 's power steadily increased : he subdued Istria and several Dalmatian cities during the reign of Irene, and his son Pepin brought Venice under Western hegemony, despite a successful counter-attack by the Byzantine fleet. Unable to counter this encroachment on Byzantine territory, Nikephoros ' successor Michael I Rangabe capitulated ; in return for the restoration of the captured territories, Michael sent Byzantine delegates to Aachen in 812 who recognized Charlemagne as Basileus. Michael did not recognize him as Basileus of the Romans, however, which was a title that he reserved for himself. This line of Roman emperors was actually generally Germanic rather than Roman, but maintained their Roman - ness as a matter of principle. These emperors used a variety of titles ( most frequently `` Imperator Augustus '' ) before finally settling on Imperator Romanus Electus ( `` Elected Roman Emperor '' ). Historians customarily assign them the title `` Holy Roman Emperor '', which has a basis in actual historical usage, and treat their `` Holy Roman Empire '' as a separate institution. To Latin Catholics of the time, the Pope was the temporal authority as well as spiritual authority, and as Bishop of Rome he was recognized as having the power to anoint or crown a new Roman emperor. The last man to be crowned by the pope ( although in Bologna, not Rome ) was Charles V. All his successors bore only a title of `` Elected Roman Emperor ''. This line of Emperors lasted until 1806 when Francis II dissolved the Empire during the Napoleonic Wars. Despite the existence of later potentates styling themselves `` emperor '', such as the Napoleons, the Habsburg Emperors of Austria, and the Hohenzollern heads of the German Reich, this marked the end of the Western Empire. Although there is a living heir, Karl von Habsburg, to the Habsburg dynasty, as well as a Pope and pretenders to the positions of the electors, and although all the medieval coronation regalia are still preserved in Austria, the legal abolition of all aristocratic prerogatives of the former electors and the imposition of republican constitutions in Germany and Austria render quite remote any potential for a revival of the Holy Roman Empire. For rulers of Italy after Romulus `` Augustulus '' and Julius Nepos, see list of barbarian kings. For the Roman emperors who ruled in the East after The Fall in the West, see List of Byzantine emperors. For emperors of the Holy Roman Empire in the West, see Holy Roman Emperor. See also Byzantine Emperor Imperator Imperial cult Interregnum Justitium King of Rome Roman dictator Roman Emperors family tree ; also Julio - Claudian family tree and Severan dynasty family tree Roman usurper Lists : List of Imperial Victory Titles List of Roman emperors List of Roman usurpers List of condemned Roman emperors References Jump up ^ Galinsky 2005, pp. 13 -- 14 Jump up ^ Alston 1998, p. 39 Jump up ^ Williams 1997, p. 147 Jump up ^ Heather 2005, p. 28 Jump up ^ Kazhdan 1991, p. 264 Jump up ^ İlber Ortaylı, `` Büyük Constantin ve İstanbul '', Milliyet, 28 May 2011. Jump up ^ Barnes 2009, pp. 278 -- 279 Jump up ^ Barnes 2009, pp. 279 -- 282 ^ Jump up to : The Oxford Classical Dictionary, entry ' Imperator ', Third Edition, Oxford University Press, 1996. Jump up ^ Cassius Dio, 43.44. 2. Jump up ^ Goldsworth 2010, p. 443 Jump up ^ Rees 2004, pp. 46 -- 56, 60 Jump up ^ Ostrogorsky 1957, p. 387 Jump up ^ On the imperial claims of the Grand Komnenos and international response to them, see N. Oikonomides, `` The Chancery of the Grand Komnenoi ; Imperial Tradition and Political Reality '', Archeion Pontou, 35 ( 1979 ), pp. 299 -- 332 Jump up ^ Constantine XI Palaeologus ( 1449 -- 53 ) Fall of Constantinople `` Ealo h Polis '' Jump up ^ Ostrogorsky 1957, p. 164 Jump up ^ Ostrogorsky 1957, p. 164f Jump up ^ Ostrogorsky 1957, p. 175 Jump up ^ Ostrogorsky 1957, p. 176 Jump up ^ Eichmann, Eduard ( 1942 ). Die Kaiserkrönung im Abendland : ein Beitrag zur Geistesgeschichte des Mittelalters, mit besonderer Berücksichtigung des kirchlichen Rechte, der Liturgie und der Kirchenpolitik. Echter - Verlag. p. 33. Sources Alston, Richard ( 1998 ). Aspects of Roman history, AD 14 -- 117. Psychology Press. ISBN 978 - 0 - 415 - 13237 - 4. Retrieved 2011 - 08 - 03. Barnes, Timothy ( 2009 ). `` The first Emperor : the view of late antiquity ''. In Griffin, Miriam. A Companion to Julius Caesar. John Wiley & Sons. ISBN 978 - 1 - 4443 - 0845 - 7. Galinsky, Karl ( 2005 ). The Cambridge companion to the Age of Augustus. Cambridge University Press. ISBN 978 - 0 - 521 - 80796 - 8. Retrieved 2011 - 08 - 03. Goldsworth, Adrian ( 2010 ). How Rome Fell : Death of a Superpower. Yale University Press. ISBN 9780300164268. Heather, Peter ( 2005 ). The Fall of the Roman Empire. ISBN 978 - 0 - 330 - 49136 - 5. Retrieved 2011 - 08 - 03. Kazhdan, Alexander, ed. ( 1991 ), Oxford Dictionary of Byzantium, Oxford University Press, ISBN 978 - 0 - 19 - 504652 - 6 Ostrogorsky, George ( 1957 ). History of the Byzantine State. Translated by Hussey, Joan. New Brunswick : Rutgers University Press. Rees, Roger ( 2004 ). Diocletian and the Tetrarchy. Edinburgh, UK : Edinburgh University Press. ISBN 978 - 0 - 7486 - 1661 - 9. Williams, Stephen ( 1997 ) ( 1985 ). Diocletian and the Roman recovery. New York, NY : Routledge. ISBN 978 - 0 - 415 - 91827 - 5. Retrieved 2011 - 08 - 03. Further reading Scarre, Chris. Chronicle of the Roman Emperors : The Reign - by - Reign Record of the Rulers of Imperial Rome. London : Thames & Hudson, October 1, 1995. ISBN 0 - 500 - 05077 - 5. ( hardcover ) External links De Imperatoribus Romanis Rulers of Rome `` Decadence, Rome and Romania, and the Emperors Who Were n't '', by Kelley L. Ross, Ph. D. UNRV.com The Roman Law Library List of Greatest Roman Emperors Roman and Byzantine emperors Principate 27 BC -- 235 AD Augustus Tiberius Caligula Claudius Nero Galba Otho Vitellius Vespasian Titus Domitian Nerva Trajan Hadrian Antoninus Pius Marcus Aurelius and Lucius Verus Commodus Pertinax Didius Julianus ( Pescennius Niger ) ( Clodius Albinus ) Septimius Severus Caracalla with Geta Macrinus with Diadumenian Elagabalus Severus Alexander Crisis 235 -- 284 Maximinus Thrax Gordian I and Gordian II Pupienus and Balbinus Gordian III Philip the Arab with Philip II Decius with Herennius Etruscus Hostilian Trebonianus Gallus with Volusianus Aemilianus Valerian Gallienus with Saloninus and Valerian II Claudius Gothicus Quintillus Aurelian Tacitus Florian Probus Carus Carinus and Numerian Gallic Emperors : Postumus ( Laelianus ) Marius Victorinus ( Domitianus II ) Tetricus I with Tetricus II as Caesar Dominate 284 -- 395 Diocletian ( whole empire ) Diocletian ( East ) and Maximian ( West ) Diocletian ( East ) and Maximian ( West ) with Galerius ( East ) and Constantius Chlorus ( West ) as Caesares Galerius ( East ) and Constantius Chlorus ( West ) with Severus ( West ) and Maximinus II ( East ) as Caesares Galerius ( East ) and Severus ( West ) with Constantine the Great ( West ) and Maximinus II ( East ) as Caesares Galerius ( East ) and Maxentius ( West ) with Constantine the Great ( West ) and Maximinus II ( East ) as Caesares Galerius ( East ) and Licinius I ( West ) with Constantine the Great ( West ) and Maximinus II ( East ) as Caesares Maxentius ( alone ) Licinius I ( West ) and Maximinus II ( East ) with Constantine the Great ( Self - proclaimed Augustus ) and Valerius Valens Licinius I ( East ) and Constantine the Great ( West ) with Licinius II, Constantine II, and Crispus as Caesares ( Martinian ) Constantine the Great ( whole empire ) with son Crispus as Caesar Constantine II Constans I Magnentius with Decentius as Caesar Constantius II with Vetranio Julian Jovian Valentinian the Great Valens Gratian Valentinian II Magnus Maximus with Victor Theodosius the Great ( Eugenius ) Western Empire 395 -- 480 Honorius Constantine III with son Constans II Constantius III Joannes Valentinian III Petronius Maximus with Palladius Avitus Majorian Libius Severus Anthemius Olybrius Glycerius Julius Nepos Romulus Augustulus Eastern / Byzantine Empire 395 -- 1204 Arcadius Theodosius II Pulcheria Marcian Leo I the Thracian Leo II Zeno ( first reign ) Basiliscus with son Marcus as co-emperor Zeno ( second reign ) Anastasius I Dicorus Justin I Justinian the Great Justin II Tiberius II Constantine Maurice with son Theodosius as co-emperor Phocas Heraclius Constantine III Heraklonas Constans II Constantine IV with brothers Heraclius and Tiberius and then Justinian II as co-emperors Justinian II ( first reign ) Leontios Tiberios III Justinian II ( second reign ) with son Tiberius as co-emperor Philippikos Anastasios II Theodosius III Leo III the Isaurian Constantine V Artabasdos Leo IV the Khazar Constantine VI Irene Nikephoros I Staurakios Michael I Rangabe with son Theophylact as co-emperor Leo V the Armenian with Symbatios - Constantine as junior emperor Michael II the Amorian Theophilos Michael III Basil I the Macedonian Leo VI the Wise Alexander Constantine VII Porphyrogennetos Romanos I Lekapenos with sons Christopher, Stephen and Constantine as junior co-emperors Romanos II Nikephoros II Phokas John I Tzimiskes Basil II Constantine VIII Zoë ( first reign ) and Romanos III Argyros Zoë ( first reign ) and Michael IV the Paphlagonian Michael V Kalaphates Zoë ( second reign ) with Theodora Zoë ( second reign ) and Constantine IX Monomachos Constantine IX Monomachos ( sole emperor ) Theodora Michael VI Bringas Isaac I Komnenos Constantine X Doukas Romanos IV Diogenes Michael VII Doukas with brothers Andronikos and Konstantios and son Constantine Nikephoros III Botaneiates Alexios I Komnenos John II Komnenos with Alexios Komnenos as co-emperor Manuel I Komnenos Alexios II Komnenos Andronikos I Komnenos Isaac II Angelos Alexios III Angelos Alexios IV Angelos Nicholas Kanabos ( chosen by the Senate ) Alexios V Doukas Empire of Nicaea 1204 -- 1261 Constantine Laskaris Theodore I Laskaris John III Doukas Vatatzes Theodore II Laskaris John IV Laskaris Eastern / Byzantine Empire 1261 -- 1453 Michael VIII Palaiologos Andronikos II Palaiologos with Michael IX Palaiologos as co-emperor Andronikos III Palaiologos John V Palaiologos John VI Kantakouzenos with John V Palaiologos and Matthew Kantakouzenos as co-emperors John V Palaiologos Andronikos IV Palaiologos John VII Palaiologos Andronikos V Palaiologos Manuel II Palaiologos John VIII Palaiologos Constantine XI Palaiologos Italics indicates a co-emperor, while underlining indicates an usurper. Ancient Rome topics Outline Timeline Epochs Foundation Kingdom overthrow Republic Empire Pax Romana Principate Dominate Western Empire fall historiography of the fall Byzantine Empire decline fall Constitution History Kingdom Republic Empire Late Empire Senate Legislative assemblies Curiate Centuriate Tribal Plebeian Executive magistrates SPQR Government Curia Forum Cursus honorum Collegiality Emperor Legatus Dux Officium Prefect Vicarius Vigintisexviri Lictor Magister militum Imperator Princeps senatus Pontifex Maximus Augustus Caesar Tetrarch Optimates Populares Province Magistrates Ordinary Consul Censor Praetor Tribune Tribune of the Plebs Military tribune Quaestor Aedile Promagistrate Governor Extraordinary Rex Interrex Dictator Magister Equitum Decemviri Consular Tribune Triumvir Law Twelve Tables Mos maiorum Citizenship Auctoritas Imperium Status Litigation Military Borders Establishment Structure Campaigns Political control Strategy Engineering Frontiers and fortifications castra Technology Army Legion Infantry tactics Personal equipment Siege engines Navy Auxiliaries Decorations and punishments Hippika gymnasia Economy Agriculture Deforestation Commerce Finance Currency Republican currency Imperial currency Technology Abacus Numerals Civil engineering Military engineering Military technology Aqueducts Bridges Circus Concrete Domes Forum Metallurgy Roads Sanitation Thermae Culture Architecture Art Bathing Calendar Clothing Cosmetics Cuisine Hairstyles Education Literature Music Mythology Religion Romanization Sexuality Theatre Wine Society Patricians Plebs Conflict of the Orders Secessio plebis Equites Gens Tribes Naming conventions Demography Women Marriage Adoption Slavery Bagaudae Latin History Alphabet Versions Old Classical Vulgar Late Medieval Renaissance New Contemporary Ecclesiastical Romance languages Writers Latin Ammianus Marcellinus Appian Appuleius Asconius Pedianus Augustine Aurelius Victor Ausonius Boëthius Caesar Catullus Cassiodorus Censorinus Cicero Claudian Columella Ennius Eutropius Fabius Pictor Festus Florus Frontinus Fulgentius Gellius Horace Jerome Juvenal Livy Lucan Lucretius Macrobius Marcus Aurelius Martial Orosius Ovid Petronius Phaedrus Plautus Pliny the Elder Pliny the Younger Priscian Propertius Quintilian Quintus Curtius Rufus Sallust Seneca the Elder Seneca the Younger Servius Sidonius Apollinaris Statius Suetonius Symmachus Tacitus Terence Tertullian Tibullus Valerius Antias Valerius Maximus Varro Velleius Paterculus Verrius Flaccus Virgil Vitruvius Greek Arrian Cassius Dio Diodorus Siculus Dionysius of Halicarnassus Dioscorides Eusebius of Caesaria Galen Herodian Josephus Pausanias Philostratus Phlegon of Tralles Photius Plutarch Polybius Porphyrius Procopius Strabo Zonaras Zosimus Major cities Alexandria Antioch Aquileia Berytus Bononia Carthage Constantinopolis Eboracum Leptis Magna Londinium Lutetia Mediolanum Pompeii Ravenna Roma Smyrna Vindobona Volubilis Lists and other topics Cities and towns Climate Consuls Distinguished women Emperors Generals Gentes Geographers Institutions Laws Legacy Legions Nomina Tribunes Wars and battles Fiction Films History portal Retrieved from `` https://en.wikipedia.org/w/index.php?title=Roman_emperor&oldid=850778160 '' Categories : Roman emperors Ancient Roman titles Positions of authority Hidden categories : Articles containing Ancient Greek - language text All articles with unsourced statements Articles with unsourced statements from January 2010 Wikipedia articles needing clarification from May 2016 Articles with unsourced statements from March 2012 Articles with unsourced statements from June 2013 Talk Contents About Wikipedia Ænglisc Asturianu Bân - lâm - gú Bikol Central Català Cebuano Eesti Ελληνικά Español Esperanto Français 한국어 Bahasa Indonesia Íslenska Italiano Basa Jawa ქართული Latina Lietuvių Македонски मराठी Bahasa Melayu 日本 語 Occitan Português Română Scots Slovenčina Српски / srpski Suomi தமிழ் ไทย Türkçe Українська اردو Tiếng Việt 中文 Lingua Franca Nova 30 more Edit links This page was last edited on 17 July 2018, at 22 : 11 ( UTC ). Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: what was the heir to the roman empire called
Answer: Imperator Destinatus ("Destined to be Emperor")