ECHOS

plural Echoi, melody type associated with early Byzantine liturgical chant. The eight echoi (hence, the collective oktoechos) of the Byzantine system were probably derived from Syrian music, and the concept of echos is also found in Armenian, Russian, and Coptic chant. Tradition gives credit to St. John of Damascus (d. 749) for the invention of the eight Byzantine echoi, but the oktoechos is mentioned already in an early 6th-century Syrian source. The echoi are not scales but groups of melodic formulas that can be combined to form entire melodies. In a collection of Greek kanones (hymns), each melody is classified according to the echos from which formulas were selected for its composition. Like the eight modes of Gregorian chant, the echoi are grouped in four pairs. Oktoechos is also used to refer to a collection of liturgical songs, arranged according to the echos to which each text is set.