Pentecost is the festival when Christians celebrate the gift of the Holy Spirit. It means "fiftieth day". It is celebrated on the Sunday 50 days after Easter.

In the Eastern Orthodox and Greek-Catholic Churches, Pentecost is one of the 12 Great Feasts of the church year.

Pentecost falls on the tenth day after Ascension Thursday. Pentecost is also called Whitsun, Whitsunday, or Whit Sunday.

It commemorates the descent of the Holy Spirit upon the Apostles and other followers of Jesus as described in the Book of Acts.

Whit Sunday is regarded as the birthday of the Christian church, and the start of the church's mission to the world.

Ten days after Jesus ascended into heaven, the twelve apostles, Jesus' mother and family, and many other of His disciples gathered together in Jerusalem for the Jewish harvest festival that was celebrated on the fiftieth day of Passover.

The Holy Spirit descended upon the apostles, gathered in an upper room with Mary, mother of Jesus, "as a mighty, rushing wind", fulfilling Jesus promise when he "breathed on them", as recorded in John's Gospel