Flavius Gregorius was Exarch of Africa from 641-651, and afterwards Western Roman Emperor until his death in 674. A distant relative of the Heraclian dynasty, his religious fervour caused him to join the revolt of Isaac I against eastern rule, and he was rewarded with the exarchate after the death of its previous ruler. As the most senior Roman official in the African provinces, he possessed great power second only to the emperor himself, and his fleet proved instrumental in repelling an attempt by Constans II to retake the West.