Theodosius I

Theodosius I ruled from AD 379 to 395, made Nicene Christianity the state religion, and was the last emperor to govern both halves of the empire. Born in Spain around 347 to a distinguished general, he campaigned in Britain and on the Danube, and retired to his estates after his father was executed in a political purge in 376. He was recalled in 379, months after the disaster at Adrianople had destroyed the eastern field army and killed the emperor Valens, and was made Augustus of the East. He could not defeat the Goths and made a treaty in 382 admitting them into the empire as federates under their own leaders, settled south of the Danube and serving as allied units rather than as recruits. It bought peace and set a precedent that eventually dismantled the western empire. In 380 he issued the Edict of Thessalonica with his co-emperors, requiring all subjects to profess the Nicene faith, and the Council of Constantinople in 381 settled the Trinitarian doctrine against Arianism. From 391 he prohibited public and private pagan sacrifice, closed temples, and ended the Olympic Games. The Serapeum in Alexandria was destroyed by a mob. In 390 he ordered a massacre at Thessalonica in reprisal for the lynching of a garrison commander; thousands were killed in the circus. Ambrose of Milan refused him communion until he did public penance, which he performed — the first clear submission of an emperor to a bishop. He defeated two western usurpers and reunited the empire briefly. He died at Milan in 395, dividing it between his sons.

• Lived: 347 CE – 395 CE
• Nationality: Spanish
• Roles: ruler