History and cultural significance
There is an altar dating to 1800 BCE within an astronomically aligned Monte Alto complex in Guatemala.
The solstice itself may have been a special moment of the annual cycle of the year even during neolithic times. Astronomical events, which during ancient times controlled the mating of animals, sowing of crops and metering of winter reserves between harvests, show how various cultural mythologies and traditions have arisen. This is attested by physical remains in the layouts of late Neolithic and Bronze Age archaeological sites such as Stonehenge in Britain and New Grange in Ireland. The primary axes of both of these monuments seem to have been carefully aligned on a sight-line pointing to the winter solstice sunrise (New Grange) and the winter solstice sunset (Stonehenge). Significant in respect of Stonehenge is the fact that the Great Trilithon was erected outwards from the centre of the monument, i.e. its smooth flat face was turned towards the midwinter Sun. The winter solstice may have been immensely important because communities were not certain of living through the winter, and had to be prepared during the previous nine months. Starvation was common in winter between January and April, also known as the famine months. In temperate climates, the midwinter festival was the last feast celebration, before deep winter began. Most cattle were slaughtered so they would not have to be fed during the winter, so it was almost the only time of year when a supply of fresh meat was available. The majority of wine and beer made during the year was finally fermented and ready for drinking at this time. The concentration of the observances were not always on the day commencing at midnight or at dawn, but the beginning of the pre-Romanized day, which falls on the previous eve.
Explanations for parallel traditions
Symbolic
Since the event is seen as the reversal of the Sun's ebbing presence in the sky, concepts of the birth or rebirth of sun gods have been common and, in cultures using winter solstitially based cyclic calendars, the year as reborn has been celebrated with regard to life-death-rebirth deities or new beginnings such as Hogmanay's redding, a New Years cleaning tradition. In Greek mythology, the gods and goddesses met on the winter and summer solstice, and Hades was permitted on Mount Olympus. Also reversal is another usual theme as in Saturnalia's slave and master reversals.
Migration and appropriation
Many outside traditions are often adopted by neighboring or invading cultures. Some historians will often assert that many traditions are directly derived from previous ones rooting all the way back to those begun in the cradle of civilization or beyond, much in a way that correlates to speculations on the origins of languages.
Therapeutic
Even in modern cultures these gatherings are still valued for emotional comfort, having something to look forward to at the darkest time of the year. This is especially the case for populations in the near polar regions of the hemisphere. The depressive psychological effects of winter on individuals and societies are for the most part tied to coldness, tiredness, malaise, and inactivity.
Also, insufficient sunlight in the short winter days increases the secretion of melatonin in the body, throwing off the circadian rhythm with longer sleep. Exercise, light therapy, increased negative ion exposure (which can be attained from plants and well ventilated flames, burning wood or beeswax) can reinvigorate the body from its seasonal lull and relieve winter blues by decreasing melatonin secretions, increasing serotonin and temporarily creating a more even sleeping pattern.
Midwinter festivals and celebrations occurring on the longest night of the year, often calling for evergreens, bright illumination, large ongoing fires, feasting, communion with close ones, and evening physical exertion by dancing and singing are examples of cultural winter therapies that have evolved as traditions since the beginnings of civilization.