Roman civil war in Britain

The death of Commodus put into motion a series of events which eventually led to civil war. Following the short reign of Pertinax, several rivals for the emperorship emerged, including Septimius Severus and Clodius Albinus. The latter was the new governor of Britannia, and had seemingly won the natives over after their earlier rebellions; he also controlled three legions, making him a potentially significant claimant. His sometime rival Severus promised him the title of Caesar in return for Albinus's support against Pescennius Niger in the east. Once Niger was neutralised, Severus turned on his ally in Britannia — it is likely that Albinus saw he would be the next target and was already preparing for war.

Albinus crossed to Gaul in 195, where the provinces were also sympathetic to him, and set up at Lugdunum. Severus arrived in February 196, and the ensuing battle was decisive. Albinus came close to victory, but Severus's reinforcements won the day, and the British governor committed suicide. Severus soon purged Albinus's sympathisers and perhaps confiscated large tracts of land in Britain as punishment.

Albinus had demonstrated the major problem posed by Roman Britain. In order to maintain security, the province required the presence of three legions; but command of these forces provided an ideal power base for ambitious rivals. Deploying those legions elsewhere would strip the island of its garrison, leaving the province defenceless against uprisings by the native Celtic tribes and against invasion by the Picts and Scots.