Flavius Valentinianus had risen to the position of Praetorian Prefect under Emperor Jovian. After Jovian’s death, he was raised to the throne by the soldiers in Bithynia. One of his first acts as emperor was to promote his brother Valens to the rank of co-Augustus to rule the Eastern half of the Empire. However, the transition of power was complicated by the fact that the army was marching back from Jovian’s aborted invasion of Persia. Taking advantage of the power vacuum in the capital, an opportunistic relative of Jovian, Procopius, rushed ahead of the army back to Constantinople where he was declared emperor. Valentinian left Valens to deal with the usurper while his set off to establish control in the west. Valentinian set up court in Milan and spent the majority of his reign fending off the increasingly powerful German attacks along the Rhine. After falling seriously ill in 367 A.D., Valentinian appointed his young son Gratian as Augustus. By 374 A.D., Valentinian was forced to stem a new series of German assaults across the Danube. Valentinian eventually passed away after suffering a stroke in 375 A.D., apparently brought on by his frustration.