From the time they were boys in Thessalonica, the brothers could speak Slavic. When the Moravian king Ratislav, unhappy with the Latin Christianity preached in his Slavic country by Charlemagne’s German missionaries, turned to Constantinople for help, Constantine and Methodius were again summoned from their monastery and sent by Emperor Michael II to Moravia. This mission was to be their lifetime concern. In 863 the brothers reached the country (today the Czech Republic) and immediately began teaching and preaching in the Slavic language of the people. They started a school to train young men for the priesthood. They conducted the liturgical services in Slavic and eventually developed a special Slavic alphabet in order to put the Bible and the liturgy in writing.

For 5 years Constantine and Methodius worked steadily to establish Christian worship according to the forms and language of the Moravian people. They inevitably clashed with the German missionaries, who were committed to the Latin form of Christianity. The two brothers were invited to Rome in 868 by Pope Nicholas I to explain their work. The Pope was so impressed by their success that he made them both bishops and, contrary to expectation, authorized them to carry on their ministry in Slavic. Constantine, however, had no further desire for the active missionary life. He entered a monastery in Rome in 869 and took a new name, Cyril, as a sign of his new life. Fifty days later he died.

Methodius returned to Moravia and continued his efforts for 16 years more. An incident in 871 extended his influence still further. The visiting king of Bohemia was invited to dine with the Moravian king. The guest found that he and his entourage were considered heathens and were expected to sit on the floor, while the host and Bishop Methodius, as Christians, were being served at a raised table. He asked what he could expect to gain by becoming a Christian. Bishop Methodius said, “A place higher than all kings and princes.” That was enough. The king asked to be baptized, along with his wife and entire retinue and returned to Bohemia to encourage many of his people to accept the Christian faith.

Methodius’s difficulties with the Latin clergy continued to plague his later years. He was summoned to Rome again in 878 by Pope John VIII. This time the influence of the Latinists was stronger. The Pope decreed that Methodius must first read the Mass in Latin, then translate it into Slavic. The bishop returned, subdued. He died in 885. Cyril and Methodius were considered heroes by the people and were formally recognized as saints of the Roman Catholic Church in 1881.