Summary
Highlights
Following the failed Persian expedition and the death of Julian the Apostate, Jovian, a Christian emperor, briefly ruled. In 364 AD, Valentinian took control of the Western Empire, and Valens of the Eastern Empire. The recurring issue of succession led to internal conflicts, with an usurper named Procopius challenging their rule in 365 AD, only to be eliminated by Valens's troops in 366 AD.
Valentinian and Valens came to power during a complex historical period marked by barbarian invasions. In 374 AD, the Huns, a nomadic people of Mongolian origin, began to move westward, displacing other Germanic tribes like the Ostrogoths and Visigoths. Unlike previous raids, these were full-scale invasions by entire populations seeking new lands. The Visigoths, who had previously been settled within the empire by Constantine in exchange for border defense, began to rebel.
The unrest between the Visigoths and Romans escalated due to Roman disdain for the barbarians. On August 9, 378 AD, the Battle of Adrianople took place, where 15,000 Roman soldiers clashed with 10,000 Goths. The Roman army was annihilated, and Emperor Valens of the Eastern Empire was killed. This defeat highlighted the impossibility of integration and instilled fear of the enemy within Rome, despite attempts at Christianizing the Goths.
After Valens's death, Gratian, Valentinian's son, entrusted the Eastern Empire to Theodosius in 379 AD. In 380 AD, Theodosius issued the Edict of Thessalonica, proclaiming Christianity as the state religion. Christian emperors, unlike their predecessors, started promoting evangelism and showed greater clemency towards practices like branding slaves or separating families during sales. Public games involving slave deaths were also abolished. Theodosius briefly became the sole emperor after Gratian's death.
Theodosius allowed the Goths to settle in Illyricum (modern-day Croatia and Albania). However, his reign was marked by the Massacre of Thessalonica in 390 AD, where Roman citizens revolted and killed a Gothic commander. Theodosius retaliated by massacring thousands of Christians in Thessalonica, leading to his excommunication by Bishop Ambrose of Milan. Theodosius was forced to perform public penance, a symbolic act that shifted the relationship between state and church, establishing the emperor's subservience to religious authority. Theodosius later denied freedom of worship to pagans, Jews, and heretics. In 394 AD, he defeated the pagan usurper Flavius Eugenius. In 395 AD, Theodosius divided the empire between his two sons, Arcadius receiving the East and Honorius the West.