The only type of Byzantine music now surviving is Orthodox Church chant, and a group of songs in honour of the emperor, members of the royal family and high ranking church officials (patriarchs, metropolitans and bishops). We also have information on music theory, and descriptions of religious ceremonies and other celebrations telling us that people sang hymns accompanied by instrumental music. Unfortunately, we know nothing of the music played at festivals, fairs and in the theatre, apart from the fact that the Church Fathers condemned it for not cultivating the spirit, as opposed to the purifying effect of sacred music.

Byzantine music borrowed features from ancient Greek and Roman music, as well as from Jewish chant. It was originally coded by a system of limited expressive potential, which later evolved in Alexandria, Antioch and Ephesus. The first symbols indicating the relative difference of a note from the previous one (rather than absolute tonality) appeared from the 9th century. Our knowledge of the music in earlier periods mainly comes from the typika of monasteries, i.e. books of rules governing monastery life, as well as from texts by the Church Fathers. According to them, the first melodies were probably syllabic, i.e. one note corresponded to one syllable. At the end of the 9th century Byzantine music was orchestrated and changed in style (one syllable of text spanned several notes), no longer being monophonic.

The system of Byzantine musical notation went through various stages before reaching its final form in the late 12th century. This mature notation enabled the expression of complex written melodic relations using a few specific symbols, thereby offering composers the chance to perform a wide variety of rhythmic, melodic and dynamic musical variations. However, Byzantine music melodies remained restricted, as composers had to write them by selecting from one of the eight fixed modes known as tones.

Milestones in the development of Byzantine music are linked to the names or writings of key composers. Romanos the Melodist developed church hymns by making ​​them longer and more complex, while Kosmas the Hymnographer introduced new hymn types. The final form of Byzantine music, entirely free of its monophonic, syllabic past, is associated with John Koukouzelis, who placed great emphasis on melody and arranged new chants into anthologies that made up church services. This last phase of Byzantine music became the core and basis of Orthodox Church hymnography.