In 9th Century, Old Church Slavonic was adopted as the language of the liturgy in churches serving various Slavic nations. This language was gradually adapted to non-liturgical purposes and became known as the Croatian version of Old Slavonic. The two variants of the language, liturgical and non-liturgical, continued to be a part of the Glagolitic service as late as the middle of the 19th century. The earliest known Croatian Church Slavonic Glagolitic manuscripts are the "Glagolita Clozianus" and the "Vienna Folia" from the 11th century.