Easter, Easter Sunday, also: Great Sunday, the Resurrection of the Lord, in Orthodox: Pasca Mazows. A great day [1] - the oldest and most important Christian feast celebrating the Paschal Mystery of Jesus Christ: His Passion, Death and Resurrection [2] [3], celebrated by Christian Churches retaining the Nice Pronance of Faith (325). The climax of the paschal cycle. It developed from the holiday celebrated in the spirit and truth (Jn 4:24) as part of Jewish rites of pesach. Then, after separating the church from the synagogue, it became a simple annual holiday preceded by one or several days of fasting, celebrated as an overnight vigil (Paschal Eve), during which the history of salvation shown in Paschal events with the participation of Jesus Christ was told and made an Eucharistic sacrifice of a real lamb ( Cf. Paschal Message) - Son of God. And eventually adopted the form of a three-day circuit so-called A Paschal Triduum, preceded by a forty-day period of preparation (a great post) and a joyful celebration of fifty days of the Easter period until the feast of the Holy Spirit [4].