Not a single contemporary Byzantine source mentions the Christianization of Ethiopia in the fifth century, the Byzantine attempts to convert Persia at the end of the sixth, the creation of the Slavic alphabet in the ninth, or the baptism of Rus' in the tenth. These great achievements of Eastern Christianity left the Byzantines themselves perfectly indifferent. Byzantium produced a number of ardent and committed missionaries, but much more visible were the Greek intellectuals who believed that it was easier "to whitewash and Ethiopian" than to Christianize a barbarian. When Leo V acquainted the pagan Bulgars with the Christian sacraments, Theophanes Continuatus castigated him for "casting the pearls of faith before the swine". In the end, the missionary zeal of a few enthusiasts lost out to the haughty isolationism of Empire. "Pearls before the Swine" focuses on the complex relationship between the Christian pledge to "teach all nations" and Greek cultural snobbery.