The Battle of Adrianople was fought in Thrace 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. Background Constantine had, in a previous war (in 316), defeated Licinius at the Battle of Cibalae and conquered from him the entire Balkan Peninsula, with the exception of Thrace and Lower Moesia. A peace deal had been arranged, but the relationship between the two emperors remained uneasy. By 324 Constantine was ready to renew the conflict, and when his army, in pursuit of a raiding force of Visigoths, or possibly Sarmatians, crossed into Licinius' territory, an opportune casus belli was created. The reaction of Licinius to this incursion was overtly hostile, inducing Constantine to go on the offensive. Constantine invaded Thrace in force; his army was smaller than that of Licinius, but it contained many battle-hardened veterans and, as he had control of the Illyrian region, the finest-quality new recruits. Battle Licinius encamped his army in a strong position near Adrianople (Hadrianopolis), the major city of inland Thrace. Constantine advanced eastward from Thessalonica until he came to the Hebrus River, on which Adrianople stands, and set up his own camp. Licinius arranged his defensive line, of 200 stades in length, in a strong position between a height overlooking the town and the confluence of the Hebrus with a tributary. The two armies remained in position for a number of days before battle was finally joined, when Constantine took the initiative by crossing the river against a well-prepared and positioned enemy that had a superior number of soldiers. Constantine used a ruse to get his troops across the Hebrus. Having noticed a suitable crossing point where the river narrowed and was overlooked by a wooded hillside, he ordered material and ropes to be conspicuously assembled at another place on the river, well away from his chosen crossing, to give the impression that he intended to build a bridge to cross there. On the wooded hillside, he secretly assembled 5,000 foot archers and a force of cavalry. He then led his cavalry over the river crossing at the narrows, and fell on the enemy unexpectedly. The surprise attack