Pentecost is a Christian holiday celebrated 50 days after Easter, commemorating the descent of the Holy Spirit upon the apostles and other followers of Jesus, as described in the New Testament in the Book of Acts. It marks the birth of the Christian Church as it empowered the apostles to spread the message of Jesus. In many traditions, Pentecost is associated with themes of renewal and the gifts of the Holy Spirit. It is also known as Whitsun or Whitsunday in some cultures.