sentences:  The forming of Christianity as state religion dates to the time of the Eastern Orthodox missionaries (Saints) Cyril and Methodius during Basil I (r. 867–886), who baptised the Serbs sometime before helping Knez Mutimir in the war against the Saracens in 869, after acknowledging the suzerainty of the Byzantine Empire.A Serbian bishopric (Diocese of Ras) may have been founded in Stari Ras in 871 by Serbian Knez Mutimir, confirmed by the Council of Constantinople in 879–80.The Serbs and Bulgarians adopt the Old Slavonic liturgy instead of the Greek.