Because their father was an officer in a part of Greece inhabited by many Slavs, these two Greek brothers ultimately became missionaries, teachers and patrons of the Slavic peoples.
After a brilliant course of studies, Cyril (called Constantine until he became a monk shortly before his death) refused the governorship of a district such as his brother had accepted among the Slavic-speaking population. Cyril withdrew to a monastery where his brother Methodius had become a monk after some years in a governmental post.
A decisive change in their lives occurred when the Duke of Moravia (present-day Czech Republic) asked the Eastern Emperor Michael for political independence from German rule and ecclesiastical autonomy (having their own clergy and liturgy). Cyril and Methodius undertook the missionary task.
Cyril’s first work was to invent an alphabet, still used in some Eastern liturgies. His followers probably formed the Cyrillic alphabet (for example, modern Russian) from Greek capital letters. Together they translated the Gospels, the psalter, Paul’s letters and the liturgical books into Slavonic, and composed a Slavonic liturgy, highly irregular then.
That and their free use of the vernacular in preaching led to opposition from the German clergy. The bishop refused to consecrate Slavic bishops and priests, and Cyril was forced to appeal to Rome. On the visit to Rome, he and Methodius had the joy of seeing their new liturgy approved by Pope Adrian II. Cyril, long an invalid, died in Rome 50 days after taking the monastic habit.
Methodius continued mission work for 16 more years. He was papal legate for all the Slavic peoples, consecrated a bishop and then given an ancient see (now in the Czech Republic). When much of their former territory was removed from their jurisdiction, the Bavarian bishops retaliated with a violent storm of accusation against Methodius. As a result, Emperor Louis the German exiled Methodius for three years. Pope John VIII secured his release.
Because the Frankish clergy, still smarting, continued their accusations, Methodius had to go to Rome to defend himself against charges of heresy and uphold his use of the Slavonic liturgy. He was again vindicated.
Legend has it that in a feverish period of activity, Methodius translated the whole Bible into Slavonic in eight months. He died on Tuesday of Holy Week, surrounded by his disciples, in his cathedral church.
Opposition continued after his death, and the work of the brothers in Moravia was brought to an end and their disciples scattered. But the expulsions had the beneficial effect of spreading the spiritual, liturgical and cultural work of the brothers to Bulgaria, Bohemia and southern Poland. Patrons of Moravia, and specially venerated by Catholic Czechs, Slovaks, Croatians, Orthodox Serbians and Bulgarians, Cyril and Methodius are eminently fitted to guard the long-desired unity of East and West. In 1980, Pope John Paul II named them additional co-patrons of Europe (with Benedict).