Pentecost is a Christian holiday that takes place on the 50th day after Easter Sunday. It commemorates the descent of the Holy Spirit upon the Apostles and other followers of Jesus Christ while they were in Jerusalem celebrating the Feast of Weeks, as described in the Acts of the Apostles. In Western Christianity, Pentecost is celebrated on the 50th day after Easter Sunday.
The book of hours is a Christian devotional book used to pray the canonical hours. The use of a book of hours was especially popular in the Middle Ages and as a result, they are the most common type of surviving medieval illuminated manuscript. Like every manuscript, each manuscript book of hours is unique in one way or another, but most contain a similar collection of texts, prayers, and psalms, often with appropriate decorations, for Christian devotion.