Church Slavonic may refer to: Old Church Slavonic language Church Slavonic language This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Old Church Slavonic (also called Old Slavic[1]) is the first literary Slavic language, developed from the Slavic dialect of Thessalonica (modern Thessaloniki) by the 9th century Byzantine Greek missionaries, Saints Cyril and Methodius.

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He put his set of words through a large number of tests and adjustments.