Europe 312: Battle of the Milvian Bridge
In late 311 Constantine and Licinius secretly agreed to align against Maxentius and Maximinus Daza. Convinced that Licinius would attack Italy from the northeast, Maxentius was unprepared when Constantine invaded from the northwest. Marching out to confront Constantine’s army as it approached Rome, Maxentius was defeated and killed at the Milvian Bridge in October 312.
311 Constantine–Licinius alliance▲
In 311 Constantine and Licinius agreed to an alliance to divide the Roman Empire between them, with Constantine offering his half-sister Flavia Julia Constantia to Licinius as a bride. Purportedly Maximinus Daza, when he heard of the marriage, formed a counter-alliance with Maxentius in Italy, but as the wedding did not take place until months after the death of Maxentius, this seems unlikely. Well into 312, both Constantine and Licinius continued to pay lip service to Maximinus’ authority as senior Augustus.
312 Battle of Turin▲
In the spring of 312, while Licinius was massing troops near the northeastern border of Italy as a diversion, Constantine led about a quarter of his army (about 40,000 men) across the Alps to invade Italy from the northwest, catching the forces of Maxentius by surprise. After storming and capturing Segusio (Susa), Constantine met a large force of Maxentian heavy cavalry outside Augusta Taurinorum (Turin). Constantine flanked the enemy with his own cavalry then used infantry with iron-tipped clubs to unhorse them. Following this victory, Augusta Taurinorum and Mediolanum (Milan) surrendered to Constantine.
312 Siege of Verona▲
From Mediolanum, Constantine advanced on Verona and besieged a large force under Maxentius’ praetorian prefect Ruricius Pompeianus there. Although Pompeianus managed to break through the siege and gather reinforcements, he was defeated and killed by Constantine on his return. After this Verona surrendered, followed by Aquileia and the other remaining cities of northern Italy.
28 Oct 312 Battle of the Milvian Bridge▲
In October 312 Constantine marched down the Via Flaminia towards Rome where Maxentius, concerned by dissent in the city and encouraged by omens that he would not fall on the day of his accession (28 October), assembled in front of the Milvian Bridge to oppose him. Constantine, who had his own omens, by now had his soldiers adorn their shields with combined Greek letters (either chi and rho or chi and tau) that would later become symbols of imperial Christianity. When Constantine prevailed, Maxentius and his forces fled across a pontoon bridge—constructed to facilitate their movement across the Tiber—only to have it collapse and send many, including the usurper himself, to drown in the river. The following day Constantine entered Rome; he was now supreme ruler of the western Roman Empire.