351 Constantius II elevates his cousin Gallus to Caesar, and puts him in charge of the Eastern part of the Roman Empire.
351 Battle of Mursa Major: the Roman Emperor Constantius II defeats the usurper Magnentius.
355 Claudius Silvanus, accused of treason, proclaims himself Roman Emperor against Constantius II.
355 Roman Emperor Constantius II promotes his cousin Julian to the rank of Caesar, entrusting him with the government of the Prefecture of the Gauls.