ABSTRACT
This chapter examines the encounter between Byzantium and Islam in the sphere of religion. The first encounter of Islam with Orthodox Christianity took place on the battlefield, in the wars which since the seventh century have opposed the Arabs to the Greek emperors. Byzantine polemical literature has largely determined the official canonical attitude of the Church towards Islam, an attitude which is reflected in the rites of the reception of Moslem converts to Christianity. Islam not only obliged the Christians to live in a tiny enclosed world which concentrated on the liturgical cult, it also made them feel that an existence was a normal one. A large part of Leo's letter is devoted to the problems of cult and worship, in reply to Omar's attack on the Christian doctrine of the sacraments. An apologetical exposition of the Christian faith, concentrated mainly on the doctrine of the Trinity.
