Valentinian I

Valentinian I (Latin: Valentinianus; 321 – 17 November 375), sometimes known as Valentinian the Great, was Roman emperor from 364 to 375. He is the second-last emperor to govern the empire as a whole, albeit only from February to March of 364, after which he appointed Valens to rule over the Eastern half of the empire, while he remained in control of the West. The founder of the Valentinian dynasty, he is noted for his successful campaigns on the Rhine and Danube frontiers.

Born into a military family in Pannonia, Valentinian rose through the ranks under emperors Constantius II, Julian and Jovian. Following Jovian's early death, Valentinian was proclaimed emperor, and he subsequently selected his brother Valens as co-emperor. During his reign, he fought successfully against the Alamanni, Quadi, and Sarmatians, strengthening the border fortifications and conducting campaigns across the frontiers. In addition, he dispatched his general Theodosius the Elder to suppress a revolt in Africa and the Great Conspiracy, a coordinated assault on Roman Britain by Picts, Scoti, and Saxons. Valentinian suffered a fatal stroke at a meeting with Quadi envoys in Pannonia, with his sons Gratian and Valentinian II succeeding him in the western half of the empire.