This public holiday in many countries occurs the day after Pentecost (derived from the ancient Green pentekostos, "fiftieth"), or Whitsunday, which commemorates the descent of the Holy Spirit upon Jesus' apostles on the seventh Sunday after Easter and is derived from the Jewish feast of Shavuot. It was an important occasion for baptism in the early church, and the name "Whitsunday" originated from the white robes worn by the newly baptized.