On February 14 the Bulgarian Orthodox Church marks the Assumption of Constantine the Philosopher who took the name of Cyril in monkhood. Cyril came from noble parents in Thessaloniki. He studied at the Magnaura School in Constantinople. Because of his accomplishments he came to be known as Philosopher. He was appointed tutor in philosophy and librarian at the Magnaura School. 

Constantine secretly fled to the Olympus monastery in Asia Minor, where, together with his brother Methodius, created the Glagolitic alphabet and translated a number of religious books into Old Slavonic. Cyril died in Rome on February 14, 869 and was buried in the Church of St. Clement. Cyril and Methodius were proclaimed saints in the Middle Ages by both the Orthodox and the Catholic Church. On December 31, 1980, Pope John Paul II declared the Holy Brothers Cyril and Methodius co-patron saints of Europe.