The Celtic culture of the British Isles revered all green plants, but particularly mistletoe and holly. These were important symbols of fertility and were used for decorating their homes and altars.
New Christmas customs appeared in the Middle Ages. The most prominent contribution was the carol, which by the 14th century had become associated with the religious observance of the birth of Christ.
In Italy, a tradition developed for re-enacting the birth of Christ and the construction of scenes of the nativity. This is said to have been introduced by Saint Francis as part of his efforts to bring spiritual knowledge to the laity.
Saints Days have also contributed to our Christmas celebrations. A prominent figure in today's Christmas is Saint Nicholas who for centuries has been honored on December 6th. He was one of the forerunners of Santa Claus.
Another popular ritual was the burning of the Yule Log, which is strongly embedded in the pagan worship of vegetation and fire, as well as being associated with magical and spiritual powers.