Leo V the Armenian

Leo V the Armenian (Greek: Λέων ὁ Ἀρμένιος, Léōn ō Arménios; c. 775 – 25 December 820) was the Byzantine emperor from 813 to 820. He is chiefly remembered for ending the decade-long war with the Bulgars, as well as initiating the second period of Byzantine iconoclasm.

A senior general of Armenian origin, Leo distinguished himself under Nikephoros I and Michael I Rhangabe, eventually becoming the stratēgos of the Anatolic Theme. Taking advantage of Michael's defeat at the Battle of Versinikia, he forced the emperor to abdicate in his favour. He was able to withhold the blockade of Constantinople by Krum of Bulgaria and, after Krum's death, concluded a 30-year peace with his successor Omurtag.

In 815, Leo deposed Patriarch Nikephoros and reinstituted iconoclasm. He was assassinated by supporters of Michael the Amorian, one of his most trusted generals, who succeeded him on the throne in 820.

Source: Wikipedia — https://en.wikipedia.org/wiki/Leo_V_the_Armenian