Decorated trees have been in existence for centuries, though there are different stories as to their origin. It is said that evergreens were cherished as a natural symbol of rebirth and life amid the whiteness of winter. One story is that pagan families would bring a live tree into the home so the wood spirits would have a place to keep warm during the cold winter months, and bells hung in the limbs would ring if a spirit were present. Food and treats were hung on the branches for spirits to eat, and a five-point star, a symbol of the five elements, was placed atop the tree.

Mistletoe has not always been used exclusively for kissing. Norsemen viewed the plant as a symbol of peace and used it as medicine. Celtic Druids believed it to be a magical plant — and an aphrodisiac. Some say that the Celts began the tradition of kissing beneath the mistletoe, but other say that is a purely English tradition that was begun because of the plant's vibrancy during the winter and its pretty white berries.

Holly, along with ivy and mistletoe, was a symbol of fertility and everlasting life. They were traditionally used to decorate doors, windows and fireplaces. However, holly was most prized because of its prickliness — pagans believed the pricks would ward off or snag and capture evil spirits before they could enter and harm a household. [IBS]

So have a holly jolly Christmas, er, solstice - it's just about the same tradition, other than that Son of God thing.