His appellation is correctly translated as "Hrabar, the Black Robe Wearer", chernorizets being the lowest rank in the monastic hierarchy, "Hrabar" supposed to be his given name. However, sometimes he is referred to as "Chernorizets the Brave", "Brave" being the translation of "Hrabar" assumed to be a nickname. No biographical information is available about him, but his name is usually considered to be a pseudonym used by one of the other famous men of letters at the Preslav Literary School or may be even by TsarSimeon I of Bulgaria, since normally monks assume Christian names of biblical or early Christian onomastics.
''On the Letters''
Chernorizets Hrabar is the author of only one literary work, "On the Letters", one of the most admired and popular works of literature written in Old Church Slavonic. The work was supposedly written some time after the Preslav Ecclesiastical People's Council in 893, but before 921, and is the only known medieval literary work to quote the exact year of the invention of the Glagolitic alphabet. The work was partly based on Greek scholia and grammar treatises and expounded on the origin of the Glagolitic alphabet and Slavic Bible translation. In On the Letters, Chernorizets Hrabar defends the alphabet against its Greek critics and proves not only its right to existence but also its superiority to the Greek alphabet arguing that the Greek letters are neither the oldest known to man, nor divine. At the same time Chernorizets Hrabar opposes Glagolitic dogmatists and makes several suggestions as to how the alphabet can be further improved. He also provided information critical to Slavonic palaeography with his mention that the pre-Christian Slavs employed "strokes and incisions" writing that was, apparently, insufficient properly to reflect the spoken language. It is thought that this may have been a form of runic script but no authentic examples are known to have survived.
Textual criticism
The manuscript of On the Letters has been preserved in 79 copies in seven families of texts, including five contaminated manuscripts, plus four abridgements independent of the seven families. All of these families probably ultimately share a common. Not one of the textual families contains an optimal text, and none of them can be established to be the source of any other. None of the text families can be shown to have dialectal features, albeit some of the individual manuscripts in the families do have them. The protograph was written in Glagolitic, and it underwent significant change or corruption in the course of its successive transcription into seven families of Cyrillic texts. Today only Cyrillic manuscripts survive. The of all seven families give the number of the letters in the alphabet as 38, but the original Glagolitic alphabet had only 36, as attested in the acrostic of Constantine of Preslav; however, one of the abridgements instead gives the number as 37 and another gives it as 42. The oldest surviving manuscript copy dates back to 1348 and was made by the monk Laurentius for Tsar Ivan Alexander of Bulgaria. The work has also been printed in Vilnius, Moscow, Saint Petersburg, Supraśl.
