Old Slavonic is a language that was spoken in the early Middle Ages by the Slavic people who lived in Eastern Europe. It is also known as Old Church Slavonic or Old Bulgarian since it was the language used by the Slavic missionaries who spread the Christian faith in the Balkans. There are several synonyms for Old Slavonic depending on the historical context and the geographical area where it was spoken. Some of these synonyms are Old Church Slavonic, Old Bulgarian, Old Macedonian, and Old Russian. All these terms refer to the same language, but each one highlights a different aspect of its use and development over time.