As it is well known, the five classical questions to be posed to any subject of research are: who – what – when – where – why. After conducting research on the possible answers to these questions as regards the famous Codex Zographensis (Miltenov 2019), the author turns now his attention to the three Glagolitic quaternions inserted in the original manuscript in order to replace lost folia. The article intends to sum up the available information and to revisit the history of these quaternions in the light of the practices and habits of medieval scribes.
Key words: medieval Slavic manuscripts, Old Church Slavonic, Codex Zographensis, Glagolitic, scribal practices.
