Pentecost is a Christian holy day commemorating the descent of the Holy Ghost upon the disciples of Jesus Christ, according to the New Testament of the Bible. It is also known as Whitsunday, or Whit Sunday.

As recorded in the New Testament of the Bible, it was on the 50th day after Easter that the apostles were praying together and the Holy Spirit descended on them. They received the “gift of tongues” – the ability to speak in other languages – and immediately began to preach about Jesus Christ to Jewish people from all over the world who flocked to Jerusalem for the Feast of Shavuot.

Christian Pentecost became not only a commemoration of the Holy Spirit’s visit but also marks the birth of the Christian Church. Although it is not certain when Pentecost began to be observed by Christians, it may have been early as the first century. Whitsuntide, also referred to as Whitsun in modern times, is the period beginning with the Saturday before Whitsunday and ending the following Saturday.

According to church tradition, Pentecost is always about seven weeks after Easter Sunday, or 50 days after Easter, including Easter Day. In some Orthodox churches, Whitsunday is observed after the date set by the western churches. This is because some Orthodox churches still observe holidays according to the Julian calendar, which preceded the Gregorian calendar adopted by many western churches.