Responsories for Holy Week Maundy Thursday and Good Friday respectively, rather than on a sequence of names referring to Maundy Thursday, Good Friday and Holy Saturday respectively. The responsories following each lesson of these matins (so also 27) were usually sung, and these are the Tenebrae Responsoria, or the Responsories for Holy Week. The name of a collection of such responsories may also refer to the Holy Triduum, as in Orlande de Lassus' "". Maundy Thursday is the fifth day of the Holy Week (Latin: Feria V or Feria Quinta). In Latin the feast is also indicated as "In Cœna Domini" ("At the meal
Adoption of the Gregorian calendar 12 days, only 11 were skipped, and the day of the week was repeated on successive days, because at the same time the International Date Line was moved, from following Alaska's eastern border with Canada to following its new western border, now with Russia. Many of the countries of eastern Europe were Eastern Orthodox or Islamic and adopted the Gregorian calendar much later than western Christian countries. Roman Catholic countries such as the Polish–Lithuanian Commonwealth adopted the "new style" (N.S.) Gregorian calendar in 1582 (switched back in 1795 after Third Partition of Poland), but the switch to the Gregorian calendar