Maundy Thursday April 22 inclusive, but these dates fall on different days depending on whether the Gregorian calendar or Julian calendar is used liturgically. Eastern churches generally use the Julian calendar and celebrate this feast throughout the 21st century between April 1 and May 5 in the more commonly used Gregorian calendar. The liturgy held on the evening of Maundy Thursday initiates the Easter Triduum, the period which commemorates the passion, death, and resurrection of Jesus; this period includes Good Friday and Holy Saturday, and ends on the evening of Easter. The Mass of the Lord's Supper or service of worship is
Easter Monday Liturgy; while this is prescribed for all days of that week, often they are only celebrated on Monday and maybe a couple of other days in parish churches, especially in non-Orthodox countries. Also, when the calendar date of the feast day of a major saint, "e.g.", St. George or the patron saint of a church or one's name day, falls during Holy Week or on Easter Sunday, the saint's day is celebrated on Easter Monday. Easter Monday is an official holiday in the following countries. Nations on this list indicated as "Eastern Christian" observe Easter according to the Julian Calendar