Born into a wealthy and prominent family in Thessalonica, brothers Cyril and Methodius evangelized Moravia, Bohemia, and Bulgaria. Their ardent love for Christ would drive them to renounce wealth and status in order to fully commit themselves in service to the Lord. St. John Paul II proclaimed them patron saints of Europe along with St. Benedict of Nursia.
~ “O God, who enlightened the Slavic peoples through the brothers Saints Cyril and Methodius, grant that out hearts may grasp the words of your teaching, and perfect us as a people of one accord in true faith and right confession. Through our Lord Jesus Christ.”
~ from the Proper of Saints, Daily Roman Missal
Note: The Memorial of Saints Cyril and Methodius, which is ordinarily celebrated on February 14, is superseded by the Sunday Liturgy.