BOOKS AND PAPERS ON BYZANTINE MUSIC LINKS TO OTHER SITES OCTOECHOS - HISTORICAL DEVELPMENT - USE - THEMS Octoechos (liturgy) The Octoechos ( Greek Ïêôþç÷ïò; Slavonic : Октонхъ, Oktoikh , or Осмогласникъ, Osmoglasnik )-literally, the book "of the Eight Tones"-contains an eight-week cycle, providing texts to be chanted for every day