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 Saint 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 Nightsince 2009. However, when the Mass does occur at midnight, it is still commonly called “Midnight Mass”.