In the period of Muscovy, two major genres formed Russian music: the sacred music of the Orthodox Church and secular music used for entertainment. The sacred music draws its tradition from the Byzantine Empire, with key elements being used in Russian Orthodox bell ringing, as well as choral singing. Neumes were developed for musical notation, and as a result several examples of medieval sacred music have survived to this day, among them two stichera composed by Tsar Ivan IV in the 16th century.