Severus was declared Caesar by the Senate, but Pescennius Niger was hostile when he declared himself emperor.[2] This started the civil war between Niger and Severus; both gathered troops and fought throughout the territory of the empire. Due to this war, Severus allowed Clodius Albinus, whom he suspected of being a threat, to be co-Caesar so that Severus did not have to preoccupy himself with imperial governance. This move allowed him to concentrate on waging the war against Niger.[1] Most historians count Severus and Albinus as two emperors, though they ruled simultaneously.