Old Church Slavonic, also known as Old Bulgarian, or Old Macedonian, was the first literary Slavic language, based on the old Solun dialect of the Thessaloniki region by the 9th century Byzantine Greeks missionaries, Saints Cyril and Methodius, who used it for translation of the Bible and other Ancient Greek language ecclesiastica... language
Proto-Slavic is the proto-language from which Slavic languages later emerged. It was spoken before the seventh century. As with all other proto-languages, no attested writings have been found; the language has been reconstructed by applying the comparative method to all the attested Slavic languages as well as other Indo-European languages.... language (also known as Common Slavic)
