Christmas was celebrated on December 25th from about the 4th century. This placed it at about the same time as the winter solstice, the shortest day of the year. For the pagans, the solstice was a time of festivities when all the traditional rules were broken. The Romans had celebrated the feast of Saturn, or Saturnalia, with orgies and wild revelries. All rules of the normal society were overturned and slaves were placed above their masters. In the Celtic culture, there was the feast of the rising of the new light. Stonehenge is aligned so that the rising sun peeks through the stones on the dawn of the winter solstice.
These traditions were continued among the people when they became Christians. During the festivities of the twelve days of Christmas, the mighty were displaced and the humble became exalted. For example, at the Feast of the Ass, the humble donkey becomes the star of the day, present at the nativity and later elevated to carry the holy family to safety from King Herod who saw in the newborn Jesus a rival for his throne.
Another tradition during the twelve days was the Feast of Fools, where a youth would be elected to be bishop for the day. In the churches, there were seasonal masses, with special chants used only for Christmas. The Christmas season ended on January 6 with the celebration of the Baptism of Jesus . This day is also celebrated as Epiphany, the day when the Three Magi arrived to adore the Christ Child.