Following the assassination of Commodus in 192, the praetorian guard sold the empire to Didius Julianus. Preferring to choose their own candidate, the eastern legions proclaimed Pescennius Niger emperor, while those in Pannonia chose Septimius Severus. Severus marched on Rome, routing Didius, and turned on Niger' forces, besieging Byzantium and driving Niger' field army out of Asia Minor. In 194, Niger was killed and his forces defeated at the battle of Issus. Severus proceeded to invade Parthia. The Parthian campaign was inconclusive, but, despite the death of Niger, Byzantium did not capitulate until 196. Later that year, Clodius Albinus revolted. Severus marched by a circuitous route into Gaul, defeating his opponent at the close‐fought battle of Lugdunum.