Winter solstice is the shortest day of year and follows the longest night. The solstice was a 2-day sun event for the Celts at which they mourned the death of the old sun god and celebrated the birth of the new sun god. The 2 days of minimum light were aided by lighting black candles for the old sun and gold candles for the new sun. A moon goddess such as Caer Ibormeith (yew) presided over this event.
The first day of this event was concerned with the death of the sun god of the waning half of the year. He was associated with the holly tree and the lynx. The day began on the eve of winter solstice and continued until the sun's life was extinguished at the end of solstice. The color of that day was black. A needfire of elder, the death tree, was lit on the eve of winter solstice and sacrifices were made throughout the day as the solemn event took place. Only simple meals such as round oatcakes were eaten, washed down with a little water.
The eve of the 1st day of the waxing half of the year was more hopeful, with the preparation of a feast and veneration to the Great Mother (moon). Trees were ornamented and homes were decked out with scarlet berries from plants such as mistletoe, yew, ivy and holly and boughs of silver fir in honour of Artio, the deity who helps with births. The mistletoe was important because it contained the soul of the oak tree until spring.
As an act of sympathetic magic to help ensure that the son of The Great Mother would be born strong and friendly, a great birch or apple needfire was lit. The Celts spent this night chanting and dancing their way into a frenzy waiting for the newborn sun to show himself. A portion of the Yule log was saved to start the needfire of the following year.
When the new sun was born, the feast followed and the Celts ate and drank cider (or golden ale) in excess, then gave presents as charms to ensure abundance during the following year. The sun god of the waxing half of the year was associated with the bull and the oak tree.
The Coligny Calendar indicates that the Celts divided the solar year into two halves, with the solstices as the hinges. The first half started at winter solstice in the month of Giamonios (December). In the solar zodiac this was the month of the goat and in the tree calendar the festival started at the end of the month of Ruis (elder), tree of death, and ended with B (birch), the tree of new beginnings. The apple tree was known as the tree of eternal life.
The god Dianos (Bright Phase) was of paramount important, being the god of new beginnings. As a god with two heads looking in opposite directions he was associated with death and rebirth, doors, brightness and oak.