 By 324 Constantine was ready to renew the conflict and when his army, in pursuit of a raiding Visigothic, or possibly Sarmatian, force, crossed into Licinius' territory an opportune "casus belli" was created.The reaction of Licinius to this incursion was overtly hostile and this induced Constantine to go on to 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 of new recruits.