312 CE
Battle of the Milvian Bridge: Constantine defeats Maxentius at the Milvian Bridge, becoming the only Roman emperor in the West. Prior to the battle, he reportedly has a vision of a cross (labarum) with the phrase "in hoc signo vinces" ("In this sign you shall conquer"). This encourages him to convert to Christianity. Constantine enters Rome; he stages a grand adventus in the city, and is met with popular jubilation. Maxentius' body is fished out of the Tiber and decapitated. Constantine I promotes a policy of state sponsorship of Christianity, perhaps even becoming a Christian himself (see Constantine the Great and Christianity).
Conflict & Security
- October 28 – Battle of the Milvian Bridge: Constantine defeats Maxentius at the Milvian Bridge, becoming the only Roman emperor in the West. Prior to the battle, he reportedly has a vision of a cross (labarum) with the phrase "in hoc signo vinces" ("In this sign you shall conquer"). This encourages him to convert to Christianity.source
- Constantine forges an alliance with co-emperor Licinius, and offers him his half-sister, Constantia, in marriage. The Praetorian Guard and Imperial Horse Guard (equites singulares Augusti) are disbanded.source
- Emperor Maximinus Daza campaigns unsuccessfully against the Armenians.source
- Constantine I crosses the Cottian Alps with an army (40,000 men) and defeats Maxentius's generals in three battles at Turin, Brescia and Verona. Maxentius's Praetorian Prefect Ruricius Pompeianus is killed in the fighting outside Verona.source
Religion & Belief
- Constantine I promotes a policy of state sponsorship of Christianity, perhaps even becoming a Christian himself (see Constantine the Great and Christianity).source
- Constantine I adopts the words "in hoc signo vinces" as a motto, and has the letters X and P (the first letters of the Greek word Christ) emblazoned on the shields of his soldiers.source
- The Council of Carthage supports Donatism, which espouses a rigorous application and interpretation of the sacraments. These doctrines will be condemned by the Council of Arles (314).source
Crime & Justice
- October 29 – Constantine enters Rome; he stages a grand adventus in the city, and is met with popular jubilation. Maxentius' body is fished out of the Tiber and decapitated.source