君士坦丁五世
Leo IV was born on 25 January 750AD, to Emperor Constantine V and his first wife, Empress Tzitzak. Because his mother was a Khazar, Leo was given the epithet 'the Khazar'. Leo was elevated to co-emperor in 751, while still an infant. He became emperor on 14 September 775, after Constantine V died while campaigning against the Bulgarian Empire.