Octoechos

Octoechos

Oktōēchos (here transcribed "Octoechos"; Greek: Ὀκτώηχος, from ὀκτώ "eight" + ἦχος "sound, mode" called echos; Slavonic: Октоихъ, Oktoikh, or Осмогласникъ, Osmoglasnik from о́семь "eight" and гласъ "voice") is the name of the eight mode system used for the composition of religious chant in Byzantine, Syrian, Coptic, Armenian, Latin and Slavic churches since the Middle Ages. In a modified form the octoechos is still regarded as the foundation of the tradition of monodic Orthodox chant today.

Oktōēchos is also the name of a Byzantine liturgical book called the "Great Octoechos" which developed first since the Studites reform as part of the Sticherarion and replaced the former book "tropologion". According to the Octoechos, it had been composed in eight parts, each of them consisted of an analogous set of hymns for one of the eight echoi. In fact each echos subordinates various melodic models or modes than just one (in Greek those might rather be called "meloi" than "echoi"), it was more important to group chants according to its mode and to divide the year into eight-week-cycles starting in numerical order from tone 1 (echos protos, ἦχος πρῶτος) following Easter Week. This liturgical octoechos concept was the invention of monastic hymnographers at Mar Saba in Palestine and in Constantinople, and a synod held 692 in Constantinople accepted their reform which also aimed to replace the homiletic poetry of the kontakion and other forms sung during the morning service (Orthros) of the cathedral rite. Hagia Sophia and other cathedrals of the Byzantine Empire did not abandon their habits, and the eight mode system came into use not earlier than in the mixed rite of Constantinople, after the patriarchate and the court had returned from their exile in Nikaia in 1261.

The reason that another eight mode system was established by Frankish reformers during the Carolingian reform, could be that Pope Adrian I also accepted on the synod in 787 the seventh-century Eastern reform for the Western church. The corresponding "chant book" is the tonary, a list of incipits of chants ordered according to the intonation formula of each church tone and its psalmody. Later also fully notated and theoretical tonaries had been written.