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
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