Who is the brother of the emporer known as Valentinian the Great and son of Gratianus Major?
Gratian the Elder: Gratian the Elder ( ; Latin: "Gratianus Funarius" ; "Gratianus Major", "Gratian the Elder") was an Illyrian soldier of the Roman Empire who flourished in the 4th century. Gratian the Elder:  He was the father of Roman Emperors, Valentinian I and Valens, founders of the Valentinianic Dynasty. Valentinian I:  Upon becoming emperor he made his brother Valens his co-emperor, giving him rule of the eastern provinces while Valentinian retained the west.
Valens