LEO III, BYZANTINE EMPEROR

March 25, 717, to June 18, 741; b. Germaniceia, northern Syria, c. 675. Leo was transferred with his parents to Thrace by justinian ii. He first came into prominence in 705, when he helped Justinian regain his throne. Justinian rewarded him with the title of spatharius and later sent him on a mission to the Caucasus. Anastasius II appointed him strategus of the Ametolikon theme, but when Anastasius was overthrown, Leo rebelled and in 717 seized the throne for himself. His reign is known for two important developments: the checking of the expansion of the Arabs and the launching of iconoclasm. When Leo shattered the Arab siege of Constantinople in 717, he saved the empire as a whole; and when he defeated them in 740 at Acroinon, he saved Asia Minor. Iconoclasm, launched in 726 (see germanus i, patriarch), plunged the empire into a controversy that lasted more than a century; it also brought about a rift with Rome that had serious consequences. For it was as a result of this rift that Leo III removed Sicily, Calabria, and Illyricum (732–733) from the jurisdiction of the papacy and placed them under that of the Byzantine patriarchate (see anastasius, patriarch of constantinople; gregory iii, pope). Leo III was also a reformer. He issued a new legal code, the Ecloga, and made several administrative changes, but the important social and economic reforms formerly attributed to him are no longer considered to have been his work.

Bibliography: k. schenk, Kaiser Leo III (Halle 1880). g. ostrogorksy, History of the Byzantine State (Oxford 1956) 133–147.

[p. charanis]