Chernorizets Hrabar

[9] His name has been theorized as a pseudonym used by some of the other famous men of letters such as Constantine, John the Exarch, Clement of Ohrid or even by Tsar Simeon I of Bulgaria himself.

[2][10] It was partly based on Greek scholia and grammar treatises and expounded on the origin of the Glagolitic alphabet and Slavic Bible translation.

The dominant view among scholars is that Hrabar was defending Slavonic in response to Greek criticism, while others have argued that his text was a defense of Glagolithic against Cyrillic.

[14] The oldest surviving manuscript copy dates back to 1348 and was made by the monk Laurentius for Tsar Ivan Alexander of Bulgaria.

It is the earliest printed work of an early Bulgarian author, included as part of the 1578 version of Ivan Fеdorov's East Slav primer.