The commemorations on the Paschal Cycle ("Movable Cycle") depend upon the date of Pascha (Easter). The texts for this cycle are found in the "Lenten Triodion", the "Pentecostarion", and the "Octoechos", as well as the "Gospel Book" and "Apostle Book" because the daily Epistle and Gospel readings are determined by this cycle. The cycle of the "Octoechos" continues through the following great lent, so the variable parts of the lenten services are determined by both the preceding year's and the current year's dates of Easter.