script introduced into the Slavic-speaking Balkan communities in the late 9th century AD, together with the Slavonic liturgy of the Roman Catholic Church. Glagolitic script was used by Roman Catholic Slavs, while the Cyrillic alphabet was used by Eastern Orthodox Slavs; and although the origin of Glagolitic is not clear, it is probably closely related to the Cyrillic alphabet. Slavic tradition is generally inconsistent as to which script to attribute to the Eastern Orthodox “apostle to the Slavs,” St. Cyril (or Constantine). Although dissimilar to Cyrillic in letter form, Glagolitic had approximately the same number of letters as Cyrillic and identical sound values for the letters; this implies a common origin for the two systems.

The oldest extant secular materials in Glagolitic date from 1309. The script flourished in the 16th and 17th centuries but since then has been displaced by Cyrillic in Greek or Russian Orthodox areas and by the Latin alphabet elsewhere. It is still used, however, in the Slavonic liturgy in some Dalmatian and Montenegrin communities. See also Cyrillic alphabet.