Magnus Maximus

Maximus's forces confronted Gratian near Paris. Gratian's army, largely composed of barbarian auxiliaries, deserted him. Gratian fled to Lugdunum (Lyon), where he was captured and executed on Maximus's orders. Maximus then controlled Gaul, Britain, and Spain.

Magnus Maximus, a Roman general of Spanish origin stationed in Britain, was proclaimed emperor by his troops. He crossed to Gaul with a large army, challenging the legitimate Western Emperor Gratian. This act initiated a civil war in the Western Roman Empire.

The Eastern Emperor Theodosius I, unable to immediately challenge Maximus, recognized him as co-emperor in the West. Maximus was granted control of Gaul, Britain, and Spain, while Valentinian II (Gratian's half-brother) retained Italy and Africa. This temporary peace lasted four years.

Maximus invaded Italy, forcing Valentinian II to flee to Theodosius in the East. Theodosius marched west and defeated Maximus's army at the Battle of the Save (modern Sava River in Croatia). Maximus was captured at Aquileia and executed.