Gratianus was born in 359. Gratianus's full name is Flavius Gratianus Augustus. Gratianus became emperor of the Roman state in 367.
Gratianus ruled Western Rome. Gratianus tried to strengthen the Roman state in the military after Valens was killed by the Goths. Gratianus has made successful wars against the Goths. And Gratianus expelled the Goths from the Roman borders.
Gratianus is also a Christian. So Gratianus forbade Pagan worship in the whole Roman state. Gratianus tried to make all the Roman people Christian.
In 383, Gratian's troops launched a rebellion against Gratianus. Because of these rebellions, Gratianus escaped from Rome. But Gratianus was caught and killed by the rebels.