What do we call the Christian celebration of Jesus’ birth?

The story behind the answer

It is the annual Christian feast that commemorates the birth of Jesus, traditionally observed on December 25 (January 7 in some Eastern churches). By contrast, the Nativity refers to the birth event itself (often depicted in cribs and art), Advent is the season of preparation leading up to the feast, and Easter celebrates the resurrection.

In the Middle Ages, it became one of the year’s great solemnities. The name derives from “Cristes mæsse” (“Christ’s Mass”) in Old English. Medieval communities marked the Twelve Days with liturgy, feasting, charity to the poor, and popular customs like Yule logs, mummers’ plays, and nativity dramas in churches. The date was standardized in the 4th century and overlaid older Roman winter festivals, helping shape the blend of sacred ritual and seasonal celebration that characterized medieval Christendom.