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 AD. 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; his body was later taken from the river and decapitated, and his head was paraded through the streets of Rome on the day following the battle before being taken to Africa.
The Battle of the Milvian Bridge (1520–24) by Giulio Romano.
La vision de Constantin by Jacob Punel (ca. 17th century).
A coin struck in 313, depicting Constantine as the companion of a solar deity
The description from 28 October 312, "A cross centered on the Sun", fits with the atmospheric optical phenomenon of sun dog.
Marcus Aurelius Valerius Maxentius was a Roman emperor from 306 until his death in 312. Despite ruling in Italy and North Africa, and having the recognition of the Senate in Rome, he was not recognized as a legitimate emperor by his fellow emperors.
Bust, Staatliche Kunstsammlungen Dresden
The Basilica of Maxentius in the Roman Forum. Completed by his enemy Constantine, it was one of the most impressive edifices of ancient times.
Maxentius as Augustus on a follis. Legend: IMPerator Caesar MAXENTIVS Pius Felix AVGustus / AETERNITAS AUGusti Noster, the Dioscuri standing facing each other, their horses between.- M OST Q (Mint Ostia, officina Q).
Statue in the Museo Ostiense