The Christianisation of the Slavs was initiated by one of Byzantium's most learned churchmen – the patriarch Photios I of Constantinople. The Byzantine Emperor Michael III chose Cyril and Methodius in response to a request from King Rastislav of Moravia, who wanted missionaries that could minister to the Moravians in their own language. The two brothers spoke the local Slavonic vernacular and translated the Bible and many of the prayer books. As the translations prepared by them were copied by speakers of other dialects, the hybrid literary language Old Church Slavonic was created, which later evolved into Church Slavonic and is the common liturgical language still used by the Russian Orthodox Church and other Slavic Orthodox Christians. Methodius went on to convert the Serbs.