CONSTANTINE IV, BYZANTINE EMPEROR

Reigned September 668 to September 685; b. c. 652. He succeeded his father, constans ii. His reign is noted for three important developments: the checking of the Arabs before constantinople, the foundation of the Bulgarian kingdom, and the settlement of the Monothelitic controversy. The Arabs seized Cyzicus in 670 and made it their base of operations against Constantinople. Their repeated attacks against the Byzantine capital, begun in earnest in 674, were finally broken up in 678 with the aid of Greek fire. Their first attempt to break into Europe thus failed. The Bulgars had made their appearance at the mouth of the Danube in the 670s. Constantine's attempt to check them ended in disaster in 680; they crossed the Danube, occupied the territory between it and the Balkan Mountains, already settled by Slavs, and organized the first Bulgarian kingdom. The Monothelitic controversy was settled by the Council of constantino ple iii, which Constantine in consultation with Rome convened in 680. The council declared against mono thelitism, which ceased thereafter to be an issue.

Bibliography: f. dÖlger, Corpus der griechischen Urkunden des Mittelalters und der neueren Zeit, series A, Regesten (Munich 1924–32) 1:28–31. g. ostrogorsky, History of the Byzantine State, tr. j. hussey from 2d German ed. (Oxford 1956); American ed. by p. charanis (New Brunswick, N.J. 1957), 110–116.

[p. charanis]