Deck the Halls

On those boughs of holly--

Mistletoe is a symbol of peace and joy and signifies friendship and goodwill. Mistletoe was considered sacred by the Norse Scandinavians, the Druids, and the Native North Americans.
In Norse theology, when Balder, the sun god, was killed by the evil spirit Loki with an arrow shaped from a mistletoe, Balder’s mother, Frigga, wept tears of white berries, which brought him back to life. Frigga blessed the plant and bestowed a kiss on all that passed beneath it.
Druids used mistletoe as protection against ghosts, witches, and goblins, placing them over doorways, in a child’s cradle, and by the first cow calving after the New Year to protect the entire herd. Whenever enemies met under mistletoe in the forest, they had to lay down their weapons for a day. Every year, the priests cut the mistletoe from the oak tree with a golden sickle. The people would wear sprigs of holly in their hair when they went to watch.
During the Saturnalia festival, Romans used holly to honor Saturn. They gave holly wreaths decorated with images of Saturn. To avoid persecution, the early Christians decked their halls with boughs of holly. Eventually, this custom transformed from a pagan tradition to a Christian symbol of Christmas. The thorns of the mistletoe came to represent Christ’s crown.
In the 18th century, kissing under the mistletoe came to mean a promise of marriage. If a young woman stood under the mistletoe, she couldn’t be refused a kiss, although that kiss could represent anything from romance to friendship. If a girl remained unkissed, it was believed that she would not marry the coming year.