The Winter Solstice is unique among days of the year — the time of the longest night and the shortest day. The dark triumphs but only briefly. For the Solstice is also a turning point. From now on (until the Summer Solstice, at any rate), the nights grow shorter and the days grow longer, the dark wanes and the Sun waxes in power.
Many of the customs associated with the Winter Solstice (and therefore with other midwinter festivals such as St Lucy’s Day, Saturnalia, Hanukkah, New Years and Twelfth Night) derive from stories of a mighty battle between the dark and the light, which is won, naturally, by the light.
The Romans celebrated from December 17th to December 24th with a festival called Saturnalia, during which all work was put aside in favor of feasting and gambling The social order was reversed, with masters waiting on their slaves.
The Saturnalia is named after Saturn, who is often depicted with a sickle like the figures of Death or Old Father Time. Astrologically speaking, Saturn is saturnine: gloomy, old, dutiful and heavy. He was the god who ate his own children rather than let them surpass him.
For new life to flourish, for the sun to rise again, it is necessary to vanquish this gloomy old fellow. Therefore, the feasting and merriment of the midwinter season are religiously mandated in order to combat the forces of gloom.