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
Zoroastrian calendar calendar are dedicated to, and named after, a divinity or divine concept. The religious importance of the calendar dedications is very significant. Not only does the calendar establish the hierarchy of the major divinities, it ensures the frequent invocation of their names since the divinities of both day and month are mentioned at every Zoroastrian act of worship. The tradition of naming the days and months after divinities was based on a similar Egyptian custom, and dates from when the calendar was set up. "The last evidence for the use ... with Old Persian month-names ... comes from 458 BCE,