Battle of the Milvian Bridge The Battle of the Milvian Bridge took place between the Roman Emperors Constantine I and Maxentius on 28 October 312 . It takes its name from the Milvian Bridge , an important route over the Tiber . Constantine won the battle and started on the path that led him to end the Tetrarchy and become the sole ruler of the Roman Empire . Maxentius drowned in the Tiber during the battle . According to chroniclers such as Eusebius of Caesarea and Lactantius , the battle marked the beginning of Constantine ' s conversion to Christianity . Eusebius of Caesarea recounts that Constantine and his soldiers had a vision of the Christian God promising victory if they daubed the sign of the Chi - Rho , the first two letters of Christ ' s name in Greek , on their shields . The Arch of Constantine , erected in celebration of the victory , certainly attributes Constantine ' s success to divine intervention ; however , the monument does not display any overtly Christian symbolism . Historical background . The underlying causes of the battle were the rivalries inherent in Diocletian ' s Tetrarchy . After Diocletian stepped down on 1 May 305 , his successors began to struggle for control of the Roman Empire almost immediately . Although Constantine was the son of the western emperor Constantius , the Tetrarchic ideology did not necessarily provide for hereditary succession . When Constantius died on 25 July 306 , his father ' s troops proclaimed Constantine as Augustus in Eboracum ( York ) . In Rome , the favorite was Maxentius , the son of Constantius ' imperial colleague Maximian , who seized the title of emperor on 28 October 306 . But whereas Constantine ' s claim was recognized by Galerius , ruler of the Eastern provinces and the senior emperor in the empire , Maxentius was treated as a usurper . Galerius ordered his co - Augustus , Severus , to put him down in early 307 . Once Severus arrived in Italy , however , his army defected to Maxentius . Severus was captured , imprisoned , and executed . Galerius himself marched on Rome in the autumn , but failed to take the city . Constantine avoided conflict with both Maxentius and the eastern emperors for most of this period . By 312 , however , Constantine and Maxentius were engaged in open hostility with one another , although they were brothers - in ‑ law through Constantine ' s marriage to Fausta , sister of Maxentius . In the spring of 312 , Constantine gathered his forces and decided to oust Maxentius himself . He easily overran northern Italy , winning two major battles : the first near Turin , the second at Verona , where the praetorian prefect Ruricius Pompeianus , Maxentius ' most senior general , was killed . Vision of Constantine . It is commonly stated that on the evening of 27 October with the armies preparing for battle , Constantine had a vision which led him to fight under the protection of the Christian God . The details of that vision , however , differ between the sources reporting it . Lactantius states that , in the night before the battle , Constantine was commanded in a dream to " delineate the heavenly sign on the shields of his soldiers " ( " On the Deaths of the Persecutors " 44 . 5 ) . He followed the commands of his dream and marked the shields with a sign " denoting Christ " . Lactantius describes that sign as a " staurogram " , or a Latin cross with its upper end rounded in a P - like fashion . There is no certain evidence that Constantine ever used that sign , opposed to the better known Chi - Rho sign described by Eusebius . From Eusebius , two accounts of the battle survive . The first , shorter one in the " Ecclesiastical History " promotes the belief that God helped Constantine but does not mention any vision . In his later " Life of Constantine " , Eusebius gives a detailed account of a vision and stresses that he had heard the story from the Emperor himself . According to this version , Constantine with his army was marching ( Eusebius does not specify the actual location of the event , but it clearly is not in the camp at Rome ) , when he looked up to the sun and saw a cross of light above it , and with it the Greek words " Εν Τούτῳ Νίκα " , " En toutō níka " , usually translated into Latin as " " in hoc signo vinces , " " both phrases have the literal meaning " In this sign , [ you shall ] conquer ; " a more free translation would be " Through this sign [ you shall ] conquer " . At first he was unsure of the meaning of the apparition , but in the following night he had a dream in which Christ explained to him that he should use the sign against his enemies . Eusebius then continues to describe the labarum , the military standard used by Constantine in his later wars against Licinius , showing the Chi - Rho sign . The accounts of the two contemporary authors , though not entirely consistent , have been merged into a popular notion of Constantine seeing the Chi - Rho sign on the evening before the battle . Both authors agree that the sign was not readily understandable to denote Christ , which corresponds to the fact that there is no certain evidence of the use of the letters " chi " and " rho " as a Christian sign before Constantine . Its first appearance is on a Constantinian silver coin from c . 317 , which proves that Constantine did use the sign at that time , though not very prominently . He made extensive use of the Chi - Rho and the Labarum only later in the conflict with Licinius . Some have interpreted the vision in a solar context ( " e . g . " , as a solar halo phenomenon ) , which may have been reshaped to fit with the Christian beliefs later expressed by Constantine . It is interesting to note that coins of Constantine depicting him quite overtly as the companion of a solar deity were minted as late as 313 , the year following the battle . The solar deity , Sol Invictus , is often pictured with a nimbus , or halo . Various emperors portrayed Sol Invictus on their official coinage , with a wide range of legends , only a few of which incorporated the epithet " invictus " , such as the legend , claiming the Unconquered Sun as a companion to the Emperor , used with particular frequency by Constantine . Constantine ' s official coinage continues to bear images of Sol until 325 / 6 . A solidus of Constantine as well as a gold medallion from his reign depict the Emperor ' s bust in profile twinned ( " jugate " ) with Sol Invictus , with the legend . The official cults of Sol Invictus and Sol Invictus Mithras were popular amongst the soldiers of the Roman army . Statuettes of Sol Invictus , carried by the standard - bearers , appear in three places in reliefs on the Arch of Constantine . Constantine ' s triumphal arch was carefully positioned to align with the colossal statue of Sol by the Colosseum , so that Sol formed the dominant backdrop when seen from the direction of the main approach towards the arch . Events of the battle . Constantine reached Rome at the end of October 312 approaching along the Via Flaminia . He camped at the location of Malborghetto near Prima Porta , where remains of a Constantinian monument in honour of the occasion are still extant . It was expected that Maxentius would remain within Rome and endure a siege , as he already had successfully employed this strategy during the invasions of Severus and Galerius . He had already brought large amounts of food to the city in preparation . Surprisingly , he decided otherwise and met Constantine in open battle . Ancient sources about the event attribute this decision either to divine intervention ( " e . g . " , Lactantius , Eusebius ) or superstition ( " e . g . " , Zosimus ) . They also note that the day of the battle was the same as the day of his accession ( 28 October ) , which was generally thought to be a good omen . Lactantius also reports that the populace supported Constantine with acclamations during circus games , although the reliability of his account is not clear . Maxentius chose to make his stand in front of the Milvian Bridge , a stone bridge that carries the Via Flaminia road across the Tiber River into Rome ( the bridge stands today at the same site , somewhat remodelled , named in Italian " Ponte Milvio " or sometimes " Ponte Molle " , " soft bridge " ) . Holding it was crucial if Maxentius was to keep his rival out of Rome , where the Senate would surely favour whoever held the city . As Maxentius had probably partially destroyed the bridge during his preparations for a siege , he had a wooden or pontoon bridge constructed to get his army across the river . The sources vary as to the nature of the bridge central to the events of the battle . Zosimus mentions it , vaguely , as being constructed in two parts connected by iron fastenings , while others indicate that it was a pontoon bridge ; sources are also unclear as to whether the bridge was deliberately constructed as a collapsible trap for Constantine ' s forces or not . The next day , the two armies clashed , and Constantine won a decisive victory . The dispositions of Maxentius may have been faulty as his troops seem to have been arrayed with the River Tiber too close to their rear , giving them little space to allow re - grouping in the event of their formations being forced to give ground . Already known as a skillful general , Constantine first launched his cavalry at the cavalry of Maxentius and broke them . Constantine ' s infantry then advanced , most of Maxentius ' s troops fought well but they began to be pushed back toward the Tiber ; Maxentius decided to retreat and make another stand at Rome itself ; but there was only one escape route , via the bridge . Constantine ' s men inflicted heavy losses on the retreating army . Finally , the temporary bridge set up alongside the Milvian Bridge , over which many of the troops were escaping , collapsed , and those men stranded on the north bank of the Tiber were either taken prisoner or killed . Maxentius ' Praetorian Guard , who had originally acclaimed him emperor , seem to have made a stubborn stand on the northern bank of the river " . . . in despair of pardon they covered with their bodies the place which they had chosen for combat . " Maxentius was among the dead , having drowned in the river while trying to swim across it in a desperate bid to escape or , alternatively , he is described as having been thrown by his horse into the river . Lactantius describes the death of Maxentius in the following manner : " The bridge in his rear was broken down . At sight of that the battle grew hotter . The hand of the Lord prevailed , and the forces of Maxentius were routed . He fled towards the broken bridge ; but the multitude pressing on him , he was driven headlong into the Tiber . " Aftermath . 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 ' head was sent to Carthage as proof of his downfall , Africa then offered no further resistance . The battle gave Constantine undisputed control of the western half of the Roman Empire . The descriptions of Constantine ' s entry into Rome omit mention of him ending his procession at the temple of Capitoline Jupiter , where sacrifice was usually offered . Though often employed to show Constantine ' s Christian sensibilities , this silence cannot be taken as proof that Constantine was a Christian at this point . He chose to honour 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 . Maxentius was condemned to " damnatio memoriae " , all his legislation was invalidated and Constantine usurped all of Maxentius ' considerable building projects within Rome , including the Temple of Romulus and the Basilica of Maxentius . Maxentius ' strongest supporters in the military were neutralized when the Praetorian Guard and Imperial Horse Guard ( " equites singulares " ) were disbanded . Constantine is thought to have replaced the former imperial guards with a number of cavalry units termed the Scholae Palatinae . Significance . Paul K . Davis writes , " Constantine ’ s victory gave him total control of the Western Roman Empire paving the way for Christianity to become the dominant religion for the Roman Empire and ultimately for Europe . " The following year , 313 , Constantine and Licinius issued the Edict of Milan , which made Christianity an officially recognised and tolerated religion in the Roman Empire . References . The most important ancient sources for the battle are Lactantius , " De mortibus persecutorum " 44 ; Eusebius of Caesarea , " Ecclesiastical History " ix , 9 and " Life of Constantine " i , 28 - 31 ( the vision ) and i , 38 ( the actual battle ) ; Zosimus ii , 15 - 16 ; and the " Panegyrici Latini " of 313 ( anonymous ) and 321 ( by Nazarius ) .