@aaaaa, It is called ”Old Church Slavonic” not ”Old Bulgarian Tartar language”, the Bulgarian Tartars did not invent Cyrillic nor did they spread the Old Church Slavonic language, they adopted it. Bulgarians are Turkic Mongols from Tartarstan and if it wasn’t for Macedonians giving the Macedonian language to the Bulgarian Tartars then youse would still be talking your Turkic Mongol language today.