The Battle of Chrysopolis was fought on 18 September 324 between the Roman emperors Constantine I and Licinius near Chrysopolis, opposite Byzantium on the Asiatic shore of the Bosphorus. The battle followed Constantine's victory at the Battle of the Hellespont, where his son Crispus destroyed the Licinian fleet. Licinius withdrew his forces from Byzantium to Chalcedon and gathered the remnants of his army, reinforced by Visigothic auxiliaries and the troops of the co-emperor Martinian.