Alexander III was the brother of Byzantine emperor Leo VI and had been named co-emperor during Leo's rule. Upon Leo's death in 912 Alexander became full emperor, and regent for Leo's son Constantine. His reign was very brief, and while the Bulgars were preparing for war against the Empire in 913, Alexander died. On his deathbed he named Constantine his heir (the boy became Constantine VII).

Preceded by:
Leo VI
Byzantine emperors Followed by:
Constantine VII