Byzantine Empire

Relations with the Slavs and Bulgars

Although imperial territory in the East could be reclaimed only by military conquest, in the Balkans and in Greece the work of reclamation could be assisted by the diplomatic weapon of evangelization. The Slavs and the Bulgars could be brought within the Byzantine orbit by conversion to Christianity. The conversion of the Slavs was instigated by the patriarch Photius and carried out by the monks Cyril and Methodius from Thessalonica. Their invention of the Slavonic alphabet (Cyrillic and Glagolitic) made possible the translation of the Bible and the Greek liturgy and brought literacy as well as the Christian faith to the Slavic peoples. The work began in the Slavic Kingdom of Moravia and spread to Serbia and Bulgaria. Latin missionaries resented what they considered to be Byzantine interference among the northern Slavs, and there were repeated clashes of interest that further damaged relations between the sees of Rome and Constantinople. The conversion of the Bulgars became a competition between the two churches and was ably exploited by the Bulgar king Boris until, in 870, he opted for Orthodox Christianity on condition of having an archbishop of his own.