Mushegh I Mamikonian was an Armenian military officer from the Mamikonian family who occupied the hereditary office of sparapet (generalissimo) of the Kingdom of Armenia under the Arsacid kings Pap and Varazdat. He took part in the Armenian resistance against the forces of the Sasanian monarch Shapur II, notably taking part in the Battle of Bagavan, where the Iranian forces were defeated. He was the regent of Armenia under the young and inexperienced Varazdat, who eventually suspected him of posing a danger to his rule, and thus had him executed, in 377/8.

Valens was Roman emperor from 364 to 378. Following a largely unremarkable military career, he was named co-emperor by his elder brother Valentinian I, who gave him the eastern half of the Roman Empire to rule. In 378, Valens was defeated and killed at the Battle of Adrianople against the invading Goths, which astonished contemporaries and marked the beginning of barbarian encroachment into Roman territory.