from
www.religioustolerance.org :
"Many symbols and practices associated with Christmas are of Pagan origin: holly, ivy, mistletoe, yule log, the giving of gifts, decorated evergreen tree, magical reindeer, etc. Polydor Virgil, an early British Christian, said "Dancing, masques, mummeries, stageplays, and other such Christmas disorders now in use with Christians, were derived from these Roman Saturnalian and Bacchanalian festivals; which should cause all pious Christians eternally to abominate them." In Massachusetts, Puritans unsuccessfully tried to ban Christmas entirely during the 17th century, because of its heathenism. The English Parliament abolished Christmas in 1647. Some contemporary Christian faith groups do not celebrate Christmas. Included among these was the Worldwide Church of God (before its recent conversion to Evangelical Christianity) and the Jehovah's Witnesses.
DRUIDISM: Druids and Druidesses formed the professional class in ancient Celtic society. They performed the functions of modern day priests, teachers, ambassadors, astronomers, genealogists, philosophers, musicians, theologians, scientists, poets and judges. Druids led all public rituals, which were normally held within fenced groves of sacred trees. The solstice is the time of the death of the old sun and the birth of the dark-half of the year. It was called "Alban Arthuan by the ancient Druids. It is the end of month of the Elder Tree and the start of the month of the Birch. The three days before Yule is a magical time. This is the time of the Serpent Days or transformation...The Elder and Birch stand at the entrance to Annwn or Celtic underworld where all life was formed. Like several other myths they guard the entrance to the underworld. This is the time the Sun God journey's thru the underworld to learn the secrets of death and life. And bring out those souls to be reincarnated." 14 A modern-day Druid, Amergin Aryson, has composed a Druidic ritual for the Winter Solstice. 15 "
Which reminds me, "The Holly and the Ivy" has been Christianized, but it was originally about the symbols of the Summer King and the Winter King, who was crowned around the time of the solstice, the changing of the seasons and the transition from dark to light, according to the folklorist (and singer) Tony Barrand, so I guess it us a somewhat mutated version of a solstice carol.