In many Western Christian traditions Midnight Mass is the first liturgy of Christmastide that is celebrated on the night of Christmas Eve, traditionally beginning at midnight when Christmas Eve gives way to Christmas Day. This popular Christmas custom is a jubilant celebration of the Mass or Service of Worship in honour of the Nativity of Jesus; even many of those Christian denominations that do not regularly employ the word "Mass" uniquely use the term "Midnight Mass" for their Christmas Eve liturgy.
The tradition of a midnight Vigil on the eve of Christmas began in the East, and was observed in the late fourth century in Jerusalem by a Christian woman named Egeria on the night of January 5. The tradition reached the Western world in the year 430 under Pope Sixtus III in the Basilica of St Mary Major.
By the twelfth century, the practice of midnight Mass had become more widespread as all priests had been granted the faculty of celebrating three Masses on Christmas Day (previously reserved to the Pope), provided the three different propers were celebrated at their appropriate times of midnight, dawn and day.
The practice of celebrating Midnight Mass is traditional in the Roman Catholic Church, although many churches now hold their "midnight" Mass at an earlier hour. Since 2009, the Pope has celebrated this Mass at 10:00 pm, and as a result the official liturgical designation of these texts has been Mass during the Night since 2009. However, when the Mass does occur at midnight, it is still commonly called "Midnight Mass".
In Splendoribus Sanctorum is used for the Communion chant during traditional Catholic midnight mass.
Churches of the Anglican Communion also traditionally celebrate Midnight Mass for Christmas at 11 or 11:30 pm. The Church of Scotland also observes a service just before midnight which involves the singing of carols, although it does not include Mass and is called a Watchnight service (held elsewhere on New Year's Eve).
Lutheran traditions often observe midnight Mass as a part of a wider Christmas Eve Vigil.