3 July: Constantine defeats Licinius at Adrianople.
18 September: Constantine defeats Licinius a second time at Chrysopolis; Licinius survives and retreats to Nicomedia and surrenders soon thereafter. Constantine enters Nicomedia in triumph.
Constantine becomes sole Augustus of the Roman Empire.
Autumn: Constantine issues a letter to all his provincials whereby Christianity becomes the favored religion of the whole empire.
8 November: Fausta and Helena are granted the rank of Augusta.
Section and plan of the oratory of a small church founded at the Baths of Novatus in honor of S. Silvestro, under the old title of Equitius, near and above which was erected the Church of S. Silvestro and S. Martino; it is reached by a staircase, marked A, which is a continuation of the staircase from the Confession.