Battle of Cibalae participant Constantine the Great
The Battle of Cibalae was fought in 316 between the two Roman emperors Constantine I (r. 306–337) and Licinius (r. 308–324). The site of the battle, near the town of Cibalae (now Vinkovci, Croatia) in the Roman province of Pannonia Secunda, was approximately 350 kilometers within the territory of Licinius. Constantine won a resounding victory, despite being outnumbered.Background
The hostilities were prompted by Constantine's appointment of his brother-in-law, Bassianus, as Caesar. Bassianus was discovered to be intriguing against Constantine, perhaps at the prodding of his own brother Senecio, a close associate of Licinius. When Constantine demanded that Licinius hand over Senecio, Licinius refused. Constantine marched against Licinius, who responded by elevating another associate, Valens. The date of Valens' elevation as emperor probably occurred after the Battle of Cibalae.
The unreliable fasti of Hydatius dates the battle to 8 October 314, but the remaining literary and numismatic evidence point to the battle being fought in 316.