The reign of Prince Boris (852-88) is remarkable because it witnessed the definitive conversion to Christianity of Bulgaria and her ruler. It is within this period also that fell the activities of the two great ‘Slavonic’ missionaries and apostles, the brothers Cyril and Methodius, who are looked upon by all Slavs of the orthodox faith as the founders of their civilisation. Christianity had of course penetrated into Bulgaria (or Moesia, as it was then) long before the arrival of the Slavs and Bulgars, but the influx of one horde of barbarians after another was naturally not propitious to its growth. The conversion of Boris in 865, which was brought about largely by the influence of his sister, who had spent many years in Constantinople as a captive, was a triumph for Greek influence and for Byzantium. Though the Church was at this time still nominally one, yet the rivalry between Rome and Constantinople had already become acute, and the struggle for spheres of spiritual influence had begun. It was in the year 863 that the Prince of Moravia, anxious to introduce Christianity into his country in a form intelligible to his subjects, addressed himself to the Emperor Michael III for help. Rome could not provide any suitable missionaries with knowledge of Slavonic languages, and the German, or more exactly the Bavarian, hierarchy with which Rome entrusted the spiritual welfare of the Slavs of Moravia and Pannonia used its greater local knowledge for political and not religious ends. The Germans exploited their ecclesiastical influence in order completely to dominate the Slavs politically, and as a result the latter were only allowed to see the Church through Teutonic glasses.