Octoechos of the First Tone (Oktoih prvoglasnik) is the first book printed in the Cyrillic script among the South Slavs. It was finished on 4 January 1494. There are 108 copies of this book existing.
The First Tone Octoechos (Oktoih prvoglasnik), a significant historical document, is the first Cyrillic-script book printed among South Slavs and was finished on January 4th, 1494.  There are 108 copies of this book in existence.