What and why are the twelve days of Christmas?
I don’t know about the “why,” but the Twelve Days of Christmas is the period of time between Christmas Day (December 25) and the Feast of the Ephiphany (January 6). In many ways, it encompasses the Christian season of Christmas because it starts with the birth of Jesus and ends with the visit by the Magi, which many consider “Little Christmas” (the the source of the gift giving traditions) and/or the birth announcement of Jesus to the outside world.