Byzantine Empire under Leo III

Leo III seized the Byzantine throne in 717 as the empire faced a major Umayyad assault on Constantinople. The successful defence of the capital in 717–718 strengthened his position and marked an important check on further Umayyad expansion into southeastern Europe. His reign followed decades of internal instability and continuing pressure on Byzantine frontiers.

After the siege, Leo reorganised imperial authority and continued warfare against Arab forces in Anatolia. His reign is also associated with the beginning of the Byzantine Iconoclast controversy, although the precise development and enforcement of early iconoclast policy remain debated by historians.

Theodore Brun’s A Savage Moon opens in Byzantium in 718, with the siege over and Emperor Leo’s government providing the political background to Erlan and Lilla’s attempt to return north.