The Glagolitic script is the oldest Slavic script, created by Constantine-Cyril (see also Old Church Slavic, Canonical) in the 9th century CE. The article first examines the problem of the creation of the Glagolitic, described in literature as “the eternal controversy” or “questio diabolica” of Slavic studies. The issue of primacy of the Glagolitic and the Cyrillic scripts and the time of the former’s invention are resolved, and the most important theories on how Constantine-Cyril created the Glagolitic are pre…