During his reign he had to solve the theological problems introduced during the reign of Julian. He removed the Arian bishops and reaffirmed the Nicene Creed. He also faced a rebellion from Procopius, a relative of Julian on his mother's side, who was believed to have a better claim to the throne. Following months of army units and cities in Thrace and Asia Minor switching sides, Valens managed to defeat his army at Thyatria in Lydia in 366, and Procopius was executed on May 27 of the same year.
The Goths themselves were displaced by invasions from the Huns around 376. They sought refuge within the borders of the empire, and when Valens refused they crossed to the Roman side of the Danube River anyway. In 378 Valens led an army to meet the Goths at Adrianople, but was completely defeated; Valens himself was among those killed.
Valentinian I (364 - 375)
Gratianus (375 - 383),
Valentinian II (375 - 392)