A.D. 860
Greek missionary Cyril adapts a Greek-based alphabet to represent the language of the South Slavs in Central Europe. Originally invented to facilitate the evangelization of Christianity to South Slavs, the alphabet became the system of writing for nearly all speakers of Slavic languages. This alphabet continues to be used to the present day, but with some revisions.
See Encarta online article "Alphabet"
Megan Sapp