Old Church Slavonic
Human language
Old Church Slavonic or Old Slavonic is the first Slavic literary language.
Historians credit the 9th-century Byzantine missionaries Saints Cyril and Methodius with standardizing the language and ... Wikipedia
Language families: Indo-European languages, Slavic languages, and South Slavic languages
ISO 639-3: (includes Church Slavonic)
Writing system: Glagolitic, Cyrillic