Slavic paganism, Slavic mythology, or Slavic religion refer to the religious beliefs, myths, and ritual practices of the Slavs before Christianisation, which occurred at various stages between the 8th and the 13th century.
The South Slavs, who likely settled in the Balkans during the 6th–7th centuries AD, bordering with the Byzantine Empire to the south, came under the sphere of influence of Eastern Christianity relatively early, beginning with the creation of writing systems for Slavic languages (first Glagolitic, and then Cyrillic script) in 855 by the brothers Saints Cyril and Methodius and the adoption of Christianity in Bulgaria in 864 and 863 in Great Moravia. The East Slavs followed with the official adoption in 988 by Vladimir the Great of Kievan Rus'.