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.) LEo VI., surnamed THE

WISE and THE PHILOSOPHER, Byzantine emperor, 886–911 . He was a weak minded ruler, chiefly occupied with unimportant wars with barbarians and struggles with churchmen . The chief event of his reign was the capture of Thessalonica (904) by Mahommedan pirates (described in The Capture of Thessalonica by John Cameniata) under the renegade Leo of Tripolis . In Sicily and Lower Italy the imperial arms were unsuccessful, and the Bulgarian Symeon, who assumed the title of " Czar of the Bulgarians and autocrat of the Romaei" secured the independence of his church by the establishment of a patriarchate . Leo's somewhat absurd surname may be explained by the facts that he " was less ignorant than the greater part of his contemporaries in church and state, that his education had been directed by the learned Photius, and that several books of profane and ecclesiastical science were composed by the pen, or in the name, of the imperial philosopher " (Gibbon) . His works include seventeen Oracula, in iambic verse, on the destinies of future emperors and patriarchs of Constantinople; thirty-three Orations, chiefly on theological subjects (such as church festivals); Basilica, the completion of the digest of the laws of Justinian, begun by Basil I., the father of Leo; some epigrams in the Greek Anthology; an iambic lament on the melancholy condition of the empire; and some palindromic verses, curiously called KapKivol (crabs) . The treatise on military tactics, attributed to hiin, is probably by Leo III., the Isaurian . Complete edition in Migne, Patrologia Graeca, cvii.; for the, literature of individual works see C . Krumbacher, Geschichte der byzantinischen Litteratur (1897) . (J . H .