317 CE
Constantine the Great and Licinius fight at the Battle of Mardia, where both sides take heavy losses. They agree to promote Crispus, Constantine II, and Licinius II to Caesars.
324 CE
July
July
Crispus, the son of Constantine the Great, achieves a huge naval victory over Licinius at the Battle of the Hellespont.
326 CE
June
June
Constantine the Great executes his son Crispus for reasons still unknown.