Chernorizets Hrabar (, Črĭnorizĭcĭ Hrabrŭ, ) was a Bulgarian monk, scholar and writer who worked at the Preslav Literary School at the end of the 9th and the beginning of the 10th century. Name His appellation is correctly translated as "Hrabar, the Black Robe Wearer" (i.e., Hrabar The Monk), chernorizets being the lowest rank in the monastic hierarchy (translatable as "black robe-wearer", see wikt:Reconstruction:Proto-Slavic/čьrnъ and wikt:riza), "Hrabar" ("Hrabr") supposed to be his given name. However, sometimes he is referred to as "Chernorizets the Brave", "Brave" which is 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 maybe even by Tsar Simeon I of Bulgaria (893-927) since normally monks assume Christian names of biblical or early Christian onomastics. On the Letters Chernorizets Hrabar is (as far as is known) the author of only one literary work, "On the Letters" (, O pismenĭhŭ, ), one of the most admired and popular works of literature written in Old Church Slavonic. The work was supposedly written sometime 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 (855). 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 exist 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 paleography with his mention that the pre-Christian Slavs employed "strokes and incisions" (, črŭty i rězy, translated as "tallies and sketches" below) 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