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 text, is the first Cyrillic-script book printed among South Slavs and was completed on January 4th, 1494.  There are currently 108 copies of this book in existence.