Pentecost (also called Whit Sunday, Whitsunday or Whitsun) is a Christian holiday which takes place on the 49th day (50th day when inclusive counting is used) after Easter. It commemorates the descent of the Holy Spirit upon the Apostles of Jesus, Mary, and other followers of the Christ, while they were in Jerusalem celebrating the Feast of Weeks, as described in the Acts of the Apostles (Acts 2:1–31). Pentecost marks the "Birthday of the Church".
Pentecost is one of the Great feasts in the Eastern Orthodox Church, a Solemnity in the Roman Rite of the Catholic Church, a Festival in the Lutheran Churches, and a Principal Feast in the Anglican Communion. Many Christian denominations provide a special liturgy for this holy celebration. Since its date depends on the date of Easter, Pentecost is a "moveable feast". The Monday after Pentecost is a legal holiday in many European, African and Caribbean countries.