In winter, trees lose their leaves revealing the perennially green mistletoe.  Ancient druids noted this fact.  Later Christians latched onto this and proclaimed the mistletoe as symbol of eternal life.

Mistletoe : Also known as the golden bough.  Held sacred by both the Celtic Druids and the Norseman.

Once called Allheal, used in folk medicine to cure many ills.  North American Indians used it for toothache, measles and dog bites.  Today the plant is still used medicinally, though only in skilled hands...it's a powerful plant.

It was also the plant of peace in Scandinavian antiquity.   If enemies met by chance beneath it in a forest, they laid down their arms and maintained a truce until the next day.

Mistletoe was used by the Druid priesthood in a very special ceremony held around this time...five days after the New Moon following winter solstice, to be precise.  The Druid priests would cut mistletoe from a holy oak tree with a golden sickle.   The branches had to be caught before they touched the ground.

Celts believed this parasitic plant held the soul of the host tree.

The priest then divided the branches into many sprigs and distributed them to the people, who hung them over doorways as protection against thunder, lightning and other evils.   The folklore, and the magical powers of this plant, blossomed over the centuries  A sprig placed in a baby's cradle would protect the child from faeries.  Giving a sprig to the first cow calving after New Year would protect the entire herd.  And so forth.

Although many sources say that kissing under the mistletoe is a purely English custom, there's another, more charming explanation for its origin that extends back into Norse mythology.   It's the story of a loving, if overprotective, mother.

The Norse god Balder was the best loved of all the gods.  His mother was Frigga, goddess of love and beauty.  She loved her son so much that she wanted to make sure no harm would come to him.  So she went through the world, securing promises from everything that sprang from the four elements--fire, water, air, and earth-- that they would not harm her beloved Balder.

Leave it to Loki, a sly, evil spirit, to find the loophole.  The loophole was mistletoe.  He made an arrow from its wood.   To make the prank even nastier, he took the arrow to Hoder, Balder's brother, who was blind.  Guiding Holder's hand, Loki directed the arrow at Balder's heart, and he fell dead.

Frigga's tears became the mistletoe's white berries.   In the version of the story with a happy ending, Balder is restored to life, and Frigga is so grateful that she reverses the reputation of the offending plant--making it a symbol of love and promising to bestow a kiss upon anyone who passes under it.