Battle of Adrianople: Constantine I defeats Licinius, who flees to Byzantium.
The Battle of Adrianople was fought on July 3, 324, during a Roman civil war, the second to be waged between the two emperors Constantine I and Licinius. Licinius was soundly defeated, his army suffering heavy casualties as a result. Constantine built up military momentum, winning further battles on land and sea, eventually leading to the final defeat of Licinius at Chrysopolis.