Cyril was born in Thessalonica and was called Constantine before becoming a monk. With his brother Methodius he prepared worship texts in Slavonic, making them accessible beyond Greek and Latin. He died in Rome; the disciples continued the work after both brothers had died. Created the Glagolitic alphabet. Worked with Methodius on Slavonic translations. Took part in the mission to Great Moravia. His story helps distinguish the two Slavonic alphabets and their origins.
Where you meet Cyril
Fyodor Uspensky · Public domain · Wikimedia Commons