Both brothers were born in Thessalonica and knew Slavic, the language spoken in Macedonia at that time.
Constantine was the real name of the younger brother, who only received the name Cyril when he became a monk shortly before his death. He studied in Constantinople, was ordained a priest, and was a scholar of philosophy.
Michael, the older brother, served as governor of a Byzantine Slavic province. He later left this position to become a monk in Bithynia, where he took the name Methodius and became the head of the monastery (igumen). The emperor sent both brothers as missionaries to the Khazars. Later, when Prince Rastislav of Moravia asked Emperor Michael III for priests who spoke Slavic, Cyril and Methodius were sent to Moravia.
The greatest achievement of these missionaries was their ability to adapt to the culture of the people they evangelized. They created the Slavic alphabet and translated the Holy Scriptures and the liturgy into that language. These new methods caused tensions with the Latin missionaries already present in the region. After spending time in Pannonia, Cyril and Methodius traveled to Rome to defend themselves against accusations. The pope approved their missionary approach, and Pope Adrian II even invited them to celebrate the sacred mysteries in Slavic in the Eternal City.
Constantine (Cyril) died in Rome on February 14, 869, and was buried in the Church of Saint Clement, where the brothers had personally brought what were believed to be the saint’s relics from Chersonesus. Pope Adrian II ordained Methodius as a priest and later appointed him Archbishop of Pannonia, with his seat in Sirmium, also naming him apostolic legate to the Slavs.
Political tensions in Moravia and rivalry with the Archbishop of Salzburg led to new conflicts. These became so serious that Methodius was imprisoned by a synod. Pope John VIII defended him but temporarily prohibited the use of the Slavic language in the liturgy and limited his jurisdiction. Methodius died on April 6, 885, and was buried with Slavic, Greek, and Latin rites.
The feast of these two saintly brothers was added to the Roman calendar in 1880 on July 5. It was later moved to July 7 and is now celebrated on Cyril’s anniversary. The Slavic pope, John Paul II, declared Cyril and Methodius co-patrons of Europe on December 31, 1980, a title that Pope Paul VI had previously given to Saint Benedict.
