Christianization of the Slavs
The Slavs were Christianized in waves from the 7th to 12th century, though the process of replacing old Slavic religious practices began as early as the 6th century. Generally speaking, the monarchs of the South Slavs adopted Christianity in the 9th century, the East Slavs in the 10th, and the West Slavs between the 9th and 12th century. Saints Cyril and Methodius (fl. 860–885) are attributed as "Apostles to the Slavs", having introduced the Byzantine-Slavic rite (Old Slavonic liturgy) and Glagolitic alphabet, the oldest known Slavic alphabet and basis for the Early Cyrillic alphabet.
Slavic Christianity refers to the history of Christianity among the Slavic peoples. The Slavic nations (or ethnic groups) are divided between Eastern Orthodoxy and Roman Catholicism. The Orthodox Slavs use the Cyrillic script, while the Catholic Slavs use the Latin script. Orthodox Slavs used the Slavic languages for liturgy from 863, firstly in Great Moravia and Bulgaria, while Catholic Slavs (like other Catholics) have only done so since the Counter-Reformation.