Pentecost

Pentecost
An Eastern Orthodox icon of the Christian Pentecost. This is the Icon of the Descent of the Holy Spirit on the Apostles. At the bottom is an allegorical figure, called Kosmos, which symbolizes the world.
Also called	Whitsunday
Observed by	Roman Catholics, Old Catholics, Protestants, Eastern Orthodox, Oriental Orthodox, Anglicans and other Christians.
Type	Christian
Significance	Celebrates the descent of the Holy Spirit upon the Apostles and other followers of Jesus
Celebrations	Religious (church) services, Festive meals, Processions, Baptism, Confirmation, Ordination, Folk customs, Dancing, Spring & woodland rites, Festive clothing.
Observances	Prayer, Vigils, Fasting (pre-festival), Novenas, Retreats, Holy Communion, Litany
Date	Easter + 49 days
2016 date	May 15 (Western) June 19 (Eastern)
2017 date	June 4 (Western) June 4 (Eastern)
2018 date	May 20 (Western) May 27 (Eastern)
Related to	Shavuot, historically and symbolically; Septuagesima, Sexagesima, Quinquagesima, Shrove Tuesday, Ash Wednesday, Lent, Palm Sunday, Maundy Thursday, Good Friday, and Holy Saturday which lead up to Easter; and Ascension, Trinity Sunday, and Corpus Christi which follow it.

May 15 (Western)

June 4 (Western)

May 20 (Western)

The Christian holiday of Pentecost (Ancient Greek: Πεντηκοστή [ἡμέρα], Pentēkostē [hēmera], "the fiftieth [day]") is celebrated 50 days from Easter Sunday, counting inclusive of Easter Sunday itself, i. e. 49 days or 7 weeks after Easter Sunday. Therefore it always occurs on a Sunday. It is also the tenth day after Ascension Thursday, which itself is 40 days from Easter, counting inclusive of Easter Sunday itself.

The Christian Pentecost is based on the New Testament, where it refers to the descent of the Holy Spirit upon the Apostles and other followers of Jesus Christ, as described in the Acts of the Apostles 2:1–31. According to Luke 22:12–13, the descent of the Holy Spirit occurred while the Apostles were celebrating the Jewish day of Shavuot (Hebrew: שבועות‎‎, lit. "Weeks"), the Feast of Weeks, a prominent feast in the calendar of ancient Israel celebrating the giving of the Law to Moses at Sinai. Subsequently, "Pentecost" may refer to the Pentecost of the New Testament and Shavuot of the Old Testament. Shavuot is a significant event shared by Jews and Christians but Christians do not commonly celebrate it as a separate holiday.

In the Christian liturgical year it became a feast commemorating what is described by some Christians as the "Birthday of the Church".