Old Slavic refers to the early form of the Slavic languages, which emerged around the 9th century. It is the ancestor of modern Slavic languages such as Russian, Polish, and Czech. Old Slavic was primarily spoken in Eastern Europe and is closely associated with the spread of Christianity, as it was used in the translation of religious texts. The most significant written record of Old Slavic is the Glagolitic alphabet, created by the brothers Cyril and Methodius. This alphabet was used to transcribe the Old Church Slavonic language, which served as a liturgical language for the Slavic peoples. Old Slavic played a crucial role in the cultural and linguistic development of the Slavic world.