Saint Cyril (his secular name is Constantine) was born in 827 AD. As for Saint Methodius, it is not known when he was born, but they are from Thessalonica. Their father’s name is Leon, but their mother is believed to be from the Slavs. Therefore, they spoke more than one language from their childhood, and this is what helped them to translate the Holy Bible. Rather, they invented Characters to herald the Slavic tribes. They studied in Constantinople, and Saint Cyril was fluent in Arabic and Hebrew. His first task was to discuss the issue of the Holy Trinity with Arab religious scholars to improve relations with the Abbasid Caliphate.

In the year 860 AD, during the time of Emperor Michael III, Saint Photius the Confessor, Patriarch of Constantinople, asked them to preach to the khagan, and upon Cyril’s return, he was appointed professor of philosophy at the university.

In the year 862 AD, the brothers began to preach after Prince Rastislav invited them. After preaching for four years, a dispute broke out between Constantinople and Rome, as the latter, after Constantinople had preached in Bulgaria, sent missionaries from the Roman Church in an attempt to bring Bulgaria into the influence of the Papal See. The Pope gave missionaries the right to preach the doctrine of “proceeding from the Father and the Son.” To return more to this topic, see the following topic: Photius as Ecumenical Patriarch.

But they continued preaching until Saint Methodius died on April 6, 885 AD. As for Saint Cyril, he died in the hope of resurrection in Rome on February 4, 869 AD.

Through the intercession of Saint Cyril and his brother Methodius, Equal to the Apostles, and through the intercessions of all the saints, O Lord Jesus Christ our God, have mercy on us and save us. Amen

The church celebrates Saints Cyril and Methodius on May 11.

Translated from Orthodox Wiki

See the Church History section for more information