Hence the Old Slavic idiom, with the pope's reluctant permission, continued to be the language of the Church service.
It is certain, that towards the close of the fifteenth century, the whole Bible was already translated into Old Slavic.
The most ancient documents of the Old Slavic language, are not older than the middle of the eleventh century.
Schlzer considers likewise the Old Slavic as a Bulgarian dialect of the ninth century.
It was during this period that his studies in the Old Slavic and Celtic languages began.