Christianity is a missionary religion by definition. Yet, as Christianity became imperial ideology, the attitude towards "barbarians" began to change: the classical Greco-Roman perception of "other" as non-human finds its way into the concept of Christianization. The author tries to outline methods of Byzantine mission, which Byzantines themselves never theoretize upon. Orthodox Christianity lost to its spiritual rivals the Nilr valley, the Middle East, Moravia, Croatia, Abkhazia, Hungary, Lithuania, Khazaria. This book explains why.