Leo III the Isaurian also known as the Syrian (Greek: Λέων Γ΄ ὁ Ἴσαυρος, Leōn III ho Isauros), ( 685 – 18 June 741) was Byzantine Emperor from 717 until his death in 741. He put an end to a period of instability, successfully defended the Empire against the invading Umayyads, and forbade the veneration of icons.