Easter known as Holy Week, is very special in the Christian tradition. The Sunday before Easter is Palm Sunday, with the Wednesday before Easter being known as Spy Wednesday. The last three days before Easter are Maundy Thursday, Good Friday and Holy Saturday (sometimes referred to as Silent Saturday). Palm Sunday, Maundy Thursday and Good Friday respectively commemorate Jesus' entry in Jerusalem, the Last Supper and the Crucifixion. Maundy Thursday, Good Friday, and Holy Saturday are sometimes referred to as the Easter Triduum (Latin for "Three Days"). Many churches begin celebrating Easter late in the evening of Holy Saturday at a
Gregorian calendar there is a system of weeks. A physical or electronic calendar provides conversion from a given date to the weekday, and shows multiple dates for a given weekday and month. Calculating the day of the week is not very simple, because of the irregularities in the Gregorian system. When the Gregorian calendar was adopted by each country, the weekly cycle continued uninterrupted. For example, in the case of the few countries that adopted the reformed calendar on the date proposed by Gregory XIII for the calendar's adoption, Friday, 15 October 1582, the preceding date was Thursday, 4 October 1582 (Julian