Constantine V, (718-775), was a Roman emperor whose reign was remarkable, internally, for the progress of Iconoclasm and, externally, for his victorious campaigns against the Bulgarians. He was the son of Leo III, and came to the throne in 741 at the age of 22.
Constantine, not content with an imperial edict banning icons, summoned an Iconoclast council (754) to condemn the pictures by means of theological argument. Fortified by the council's findings, he began a wholesale persecution of the image worshipers, and especially of the monastic orders, which he wished to extirpate. It has been said that his motives here were economic rather than religious; but modern scholarship rightly diagnoses him as a religious fanatic.
Constantine's Iconoclastic preoccupations prevented him from intervening in Italy, where Ravenna fell to the Lombards in 751, ending Byzantine rule in northern Italy; or in Syria, where the Abbasid dynasty succeeded the Ummayad dynasty in 750. But his repeated campaigns against the Bulgars (763-775) covered him with glory. Constantine died on campaign on September 14, 775.