This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Unlike most of the world's major scripts, which evolved gradually over centuries, Glagolitic appears to have been deliberately designed, essentially from scratch, for a specific purpose: giving the Slavic peoples of Great Moravia scripture and liturgy in their own language. The Byzantine missionary brothers Constantine, later known by his monastic name Cyril, and Methodius are traditionally credited with creating it around 862 to 863 CE, ahead of their mission from Constantinople into Slavic-speaking Central Europe. Scholars broadly agree the alphabet was a genuine invention rather than a natural evolution of an existing script, which makes its distinctive rounded, looping letterforms, unlike anything in Greek, Latin or Cyrillic, worth explaining. Exactly what shaped those letterforms is where agreement ends: some scholars hold that Cyril based the design mainly on a cursive form of the Greek alphabet, while others, including Vondrak, Nahtigal and Fortunatov, have argued for genuine influence from non-Greek Oriental scripts including Hebrew, Samaritan, Coptic, Armenian or Georgian, pointing to specific letter resemblances as evidence. Whatever its precise sources, Glagolitic did what it was built to do: it gave Old Church Slavonic a script of its own and made the Moravian mission's translation work possible.