TONES (Slavonic – гласи – hlasy)
The Church music of the Eastern Church is based upon eight tones. Each week has its appointed tone. On Saturday evening of the Week of Light (the eve of the Sunday of Saint Thomas), the cycle of tones commences with Tone One; and so, week by week, the sequence continues through the successive tones from one to eight, changing to a new tone every Saturday evening, and returning to Tone One after Tone Eight. The various texts in the Tone of the Week are to be found in the Octoechos. The special texts for fixed feasts (found in the Menaia) and for the days of the Great Fast and the paschal season (found in the Triodion and Pentecostarion) are set in carious tones; and these do not, save by coincidence, correspond with the appointed tone of the week.
Most Reverend Robert M. Moskal Eparch of St. Josaphat in Parma. “the Sacrifice of Praise”