Tradition ascribes the
Cyrillic alphabet to Saints Cyril and Methodius, missionaries to the
Slavs in the 9th century, but the alphabet was probably invented in
the 10th century possibly by St. Kliment of Ohrid. It is used to write
Old Church Slavonic. It has experienced revision most recently in
1917-1918 when four letters were eliminated. The form of the letters
has also changed over time.
The Russian alphabet is a
modern version of the Cyrillic alphabet with the same 30 letters. Like
Cyrillic it is based on the Greek alphabet with additional letters for
sounds missing in Greek.