emperor of the East, A. D. 780-797, the son of Leo IV. Chazarus Isaurus and Irene, was born in 771, and succeeded his father in 780, under the guardianship of his mother, a highly-gifted but ambitious and cruel woman, a native of Athens. The reign of Constantine VI. presents a hideous picture of wars, civil and religious troubles, and pitiless crimes. Elpidus, governor of the thema of Sicily, revolted in 781; and it seems that his intention was either to place himself or one of the four paternal uncles of the young emperor on the throne; but the eunuch Theodore, an able general, defeated him in several engagements in 782, and Elpidus fled with his treasures to the Arabs in Africa, by whom he was treated till his death with the honours due to an emperor. The power of the Arabs grew every year more dangerous to the empire. In 781 they suffered a severe defeat from the eunuch Joannes in Armenia, evacuated that country, and fled in confusion to Syria; but in the following year, a powerful Arabian army, divided into three strong bodies, and commanded by Harún-ar-Rashid, the son of the khalif Mahadí, penetrated as far as the Bosporus, and compelled Irene to pay an annual tribute of 60,000 pieces of gold. The peace, however, was broken some years afterwards, and the new war lasted till the end of the reign of Constantine, who in 790 lost half of his fleet in the gulf of Attalia, but obtained several victories over the Arabs by land. He was likewise victorious in a war with the Slavonians, who had conquered all Greece, but were driven back by Stauracius in 784.

At an early age, Constantine was betrothed to Rotrudis, daughter of Charlemagne; but quarrels having broken out with that emperor on the subject of the Greek dominions in Italy, the match was broken off, and Constantine married Maria, an Armenian lady, whom he repudiated three years afterwards, and married one Theodata. In 787, the sect of the Iconoclasts was condemned in the seventh general council held at Nicaea, and the worship of images was restored throughout the empire. When Constantine came of age, he was of course intrusted with the administration of the empire; but Irene's influence was so great, that she remained the real sovereign. Tired of his vassalage, Constantine intrigued against her, and had already resolved to arrest her, when the plot was discovered; his partisans were severely punished, and he himself received the chastisement of a boy from the hands of his mother. Infuriated by this outrage, the young emperor requested the assistance of his Armenian life-guard, and, having found them all devoted to him, seized upon his mother, and confined her in one of her palaces, where she was kindly treated, but was allowed to have no other company but that of her attendants. A reconciliation took place some time afterwards, but Irene finally contrived the ruin of her son.

After succeeding in being recognized as the lawful master of the empire, Constantine put himself at the head of his army, and set out to meet the Bulgarians, who were plundering all Thrace. He obtained some advantages over them, but lost a pitched battle, saw his army cut to pieces, and with difficulty escaped to Constantinople. There he received intelligence that a conspiracy against his life, formed by his four uncles and supported by the Armenian guard, was on the eve of breaking out. His measures were at once quick and energetic : he seized the conspirators, disarmed the Armenians, whose commander, Alexis, had his eyes put out, and punished his uncles with equal severity : one of them was blinded, and the three others had their tongues cut off, and they were all forced to become ecclesiastics, in order to incapacitate them for reigning. They were afterwards banished, and died in obscurity.

The reconciliation which had taken place between Constantine and his mother was a hollow one; Irene could not forget that she had once ruled, and during an expedition of her son against the Arabs she formed another conspiracy. On Constantine's return in 797, he was suddenly assailed by assassins while he was sitting in the Hippodrome to look at the races. He escaped unhurt, fled from the city, and directed his course to Phrygia. Before arriving there, he was joined by the empress and a host of partisans. Relying on the promises of Irene, he returned to Constantinople, but was surprised in his palace by a band of assassins hired by Irene and her favourite, the general Stauracius. His eyes were put out by their order with so much violence that he died on the same day. By a singular coincidence of circumstances, he was murdered in the " Porphyra," the name of the apartment where the empresses were accustomed to be confined, and where he was born. His only son, Leo, having died in his lifetime, he was succeeded by his mother Irene. Constantine VI. was the last of the Isaurian dynasty. Zonaras and Cedrenus say, that he survived his excaecation for a considerable time; but their opinion seems to be untenable, although Le Beau believes it to be correct. (Theophan. p. 382, &c., ed. Paris ; Cedren. p. 469, &c., ed. Paris; Zonar. vol. ii. p. 93, &c., ed. Paris; Joel, p. 178, ed. Paris; Glycas, p. 285, ed. Paris.