Leo III the Isaurian, also known as the Syrian (Greek: Λέων Γ΄ ὁ Ἴσαυρος), was Byzantine Emperor from 717 until his death in 741. He put an end to the Twenty Years' Anarchy, a period of great instability in the Byzantine Empire between 695 and 717, marked by the rapid succession of several emperors to the throne. He also successfully defended the Empire against the invading Umayyads and forbade the veneration of icons.
In August 720 Leo III as associated on the throne his son, Constantine V.
Constantine V succeeded his father as sole emperor on 18 June 741.