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
Determination of the day of the week since the start of the century, and then add these together along with the number of years since the start of the century, and the day number of the month. Eventually, one ends up with a day-count to which one applies modulo 7 to determine the day of the week of the date. Some methods do all the additions first and then cast out sevens, whereas others cast them out at each step, as in Lewis Carroll's method. Either way is quite viable: the former is easier for calculators and computer programs; the latter for mental calculation (it is quite