The Cyrillic alphabet (or azbuka, from the old name of the first two letters) is an alphabet used to write six natural Slavic languages (Belarusian, Bulgarian, Macedonian, Russian, Serbian, and Ukrainian) and many other languages of the former Soviet Union, Asia and Eastern Europe.
It was invented sometime during the 10th century AD. The oldest Cyrillic inscriptions have been found, dating back to the 940s. It has also been used for other languages in the past. Not all letters in the Cyrillic alphabet are used in every language which is written with it.
The plan of the alphabet is derived from the early Cyrillic alphabet, itself a derivative of the Glagolitic alphabet, a ninth century uncial cursive usually credited to two brothers from Thessaloniki, Saint Cyril and Saint Methodius. The glyphs in the Cyrillic alphabet are, however, mainly Byzantine Greek letters. Some of them, especially those representing sounds that did not exist in medieval Greek, retain their Glagolitic forms.
The modern Russian alphabet is a variant of the Cyrillic alphabet.
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