Flavius Gratianus Augustus was born in 359, was the son of Valentinian I and was named after his grandfather Gratian the Elder.
In 367 his father elevated him to Augustus and following the death of Valentinian in 375 the troops announced Gratian’s infant half-brother emperor with the title Valentinian II.
Gratian passively agreed to this set up without nessacerily approving and handed over a few provinces of the western regions to his mother to look after as his uncle Valens was still in charge of the East.
While his uncle Valens was fighting in the battle of Adrianople, Valens refused to wait for his nephews army to assist and as a result lost two thirds of the eastern roman army as well as his own life.
Upon the death of Valens, Gratian elevated Theodosius I in 379 to govern the eastern empire and together they fought in the Gothic war which raged from 377 to 382.
After time Gratian lost favour with his troops and a general by the name of Magnus Maximus took the opportunity to invade Gaul. Gratian was captured and assassinated in 383.