Cyril and Methodius were brothers who became evangelists to the Slavic people.  There were born in Thessalonica, Greece, of a well to do family .  Cyril went to school in Constantinople and later became a professor in that city.  Methodius was a governor in Slavic territory.  Methodius entered into a monastery.  Together they travelled Russia and worked on converting the Khazars to the Catholic faith.  Cyril and Methodius invented the Cyrillic language which in the language used in Russia and other Slavic countries.  Pope Adrian II (reigned 858-867) approved their mission among the Slavic people.

     Cyril died in Rome on Febraury 14, 869 after being ordained.  Methodius became the archbishop of Velebrod in the Czech Republic.  Methodius had made enemies in Germany due to the jealousy of German bishops and in 870 Methodius was imprisoned by King Louis of Germany and was imprisoned for two years before being released through the intervention of Pope John VIII.  Methodius and Cyril tranlated the Scriptures into the Cyrilic language.  The liturgical language of the Slavic people was created by Cyril and Methodius.

More on Saints Cyril and Methodius

Saints Cyril and Methodius

Saints Cyril and Mehtodius

Butler's Lives of the Saints