Leo IV the Khazar, Byzantine emperor (d. 780)
Leo IV the Khazar (Greek: Λέων Δ΄ ὁ Χάζαρος, Leōn IV ho Khazaros; 25 January 750 – 8 September 780) was Byzantine emperor from 775 to 780 AD. He was born to Emperor Constantine V and Empress Tzitzak in 750. He was elevated to caesar the next year, in 751, and married to Irene of Athens in 768. When Constantine V died in September 775, while campaigning against the Bulgarians, Leo IV became senior emperor on 14 September 775. In 778 Leo raided Abbasid Syria, decisively defeating the Abbasid army outside of Germanicia. Leo died on 8 September 780, of tuberculosis. He was succeeded by his underage son Constantine VI, with Irene serving as regent.