LEO V.

leo v., surnamed the armenian, emperor of the east, 813-820, was a distinguished general of nicephorus i. and michael i. after rendering good service on behalf of the latter in a war with the arabs (812), he was summoned in 813 to co-operate in a campaign against the bulgarians. taking advantage of the disaffection prevalent among the troops, he left michael in the lurch at the battle of adrianople and subsequently led a successful revolution against him. leo justified his usurpation by repeatedly defeating the bulgarians who had been contemplating the siege of constantinople (814-817). by his vigorous measures of repression against the paulicians and image-worshippers he roused considerable opposition, and after a conspiracy under his friend michael psellus had been foiled by the imprisonment of its leader, he was assassinated in the palace chapel on christmas eve, 820. see e. gibbon, _the decline and fall of the roman empire_ (ed. bury, 1896), v. 193-195. (m. o. b. c.)