(Θεόφιλος), emperor of Constantinople A. D. 829-842, was the son and successor of Michael II. Balbus, with whom he was associated in the government as early as 821 (Eckhel, vol. viii. p. 240.) He was engaged in war with the Saracens during the greater part of his reign, but notwithstanding his valour and energy he was generally unsuccessful against these formidable foes, and hence obtained the surname of the Unfortunate. At the end of his fifth campaign he had the mortification of seeing the city of Amorium in Phrygia, which was the birth-place of his father, and which he and his father had adorned with public buildings, levelled to the ground by the caliph Motassem. Like most of the other Byzantine emperors, Theophilus took part in the religious disputes of his age. He was a zealous iconoclast, and persecuted the worshippers of images with the utmost severity; but notwithstanding his heresy, the ancient writers bestow the highest praise upon his impartial administration of justice. He died in 842, and was succeeded by his infant son Michael III., who was left under the guardianship of his mother. the empress Theodora. MICHAEL III.] (Zonar. 15.25_29 Cedrenus, pp. 513-533 ; Continnator Theoph. lib. iii.; Ducange, Familiac Byzantinac, pp. 132, 133; Gibbon, Decline und Fall, cc. xlviii. and lii.)