The Twenty Years' Anarchy (695–717 AD) was a period of severe political instability that nearly destroyed the Byzantine Empire. Triggered by the deposition and mutilation of Emperor Justinian II, this 22-year crisis saw seven different emperors violently seize and lose the throne through rapid military coups. While internal factions fought for control of Constantinople, foreign enemies capitalized on the chaos, leading to devastating territorial losses to the Umayyad Caliphate and the Bulgars. The devastating cycle of assassinations and civil wars finally ended in 717 AD when Leo III the Isaurian seized power, successfully defended the capital from a massive Arab siege, and established a stable dynasty.