Alexander (Greek: Αλέξανδρος, Alexandros, 870 – 6 June 913), sometimes numbered Alexander III, ruled as Emperor of the Byzantine Empire in 912–913.

Alexander was the third son of Emperor Basil I and Eudokia Ingerina. Unlike his older brother Leo VI the Wise, his paternity was not disputed between Basil I and Michael III because he was born years after the death of Michael. As a child, Alexander was crowned as co-emperor by his father around 879.

Upon the death of his brother Leo on 11 May 912, Alexander succeeded as senior emperor alongside Leo's young son Constantine VII. He was the first Byzantine emperor to use the term "" (αὐτοκράτωρ πιστὸς εὑσεβὴς βασιλεὺς) on coinage to celebrate the ending of his thirty-three years as co-emperor. Alexander promptly dismissed most of Leo's advisers and appointees, including the admiral Himerios, the patriarch Euthymios, and the Empress Zoe Karbonopsina, the mother of Constantine VII whom he locked up in a nunnery. The patriarchate was again conferred on Nicholas Mystikos, who had been removed from this position because he had opposed Leo's fourth marriage. During his short reign, Alexander found himself attacked by the forces of Al-Muqtadir of the Abbasid Caliphate in the East, and provoked a war with Simeon I of Bulgaria by refusing to send the traditional tribute on his accession. Alexander died of exhaustion after a game of tzykanion on June 6, 913, allegedly fulfilling his brother's prophecy that he would reign for 13 months.

...
Wikipedia