In 862, the holy brothers Cyril and Methodius created the Glagolitza - the first Slavic alphabet, which served as a script for Old Slavonic language. The Glagolitza is a system of graphs. It was consisted of 41 (later 38) letters that accurately reflect the sound characteristics of the Old Macedonian language. The name Glagolitza comes from the word "glagol", which means "verb". Since "verb" means "to speak," the Glagolitza is poetically called "the letters that speak".
Glagolitza (small letters present the Cyrillic alphabet)

Cyrillic alphabet is derived from the older Glagolitic alphabet, including some ligatures. The script is named in honor of the two Byzantine brothers, Saints Cyril and Methodius, who created the Glagolitic alphabet earlier on. Modern scholars believe that Cyrillic was developed and formalized by early disciples of Cyril and Methodius, Kliment and Naum who transformed and simplified the new and varied Glagolitic alphabet. It is composed of 31 letters.
The Cyrillic Alphabet, based on the Glagolitza, is still used in various Slavonic languages. About 10% of the countries in the world write in Cyrillic. The Cyrillic alphabet is the third official alphabet of the EU after the Latin alphabet and the Greek alphabet.