Upon becoming emperor Valentinian I made his brother Valens his co-emperor, giving him rule of the eastern provinces while Valentinian retained the west. During his reign, Valentinian successfully fought the Alamanni, Quadi, and Sarmatians. Most notable was his victory over the Alamanni in 367 at the Battle of Solicinium. His brilliant general Count Theodosius defeated a revolt in Africa, and the Great Conspiracy, a coordinated assault on Roman Britain by Picts, Scots, and Saxons. Valentinian was the last emperor to conduct campaigns across both the Rhine and Danube rivers. He rebuilt and improved the fortifications along the frontiers, even building fortresses in enemy territory. He founded the Valentinian Dynasty, with his sons Gratian and Valentinian II succeeding him in the western half of the empire. Due to the successful nature of his reign and almost immediate decline of the empire after his death, he is often considered the "last great western emperor."