It’s a shame the solstice is no longer on - or fluctuating around - December 25th. It would be nice for that day to have some real, physical significance.
In 46 BCE, Julius Caesar in his Julian calendar established December 25 as the date of the winter solstice of Europe (Latin: Bruma). Since then, the difference between the calendar year (365.2500 days) and the tropical year (~365.2421897 days) moved the day associated with the actual astronomical solstice forward approximately three days every four centuries, arriving to December 12 during the 16th century. In 1582, Pope Gregory XIII decided to restore the exact correspondence between seasons and civil year but, doing so, he did not make reference to the age of the Roman dictator, but to the Council of Nicea of 325, as the period of definition of major Christian feasts. So, the Pope annulled the 10-day error accumulated between the 16th and the 4th century, but not the 3-day one between the 4th AD and the 1st BC century. This change adjusted the calendar bringing the northern winter solstice to around December 22. Yearly, in the Gregorian calendar, the solstice still fluctuates a day or two but, in the long term, only about one day every 3000 years.
And more from Wikipedia:
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.
Influenced by the Ancient Greek Lenaia festival (held in honour of Dionysus), Brumalia was an ancient Roman solstice festival honoring Bacchus, generally held for a month and ending December 25. The festival included drinking and merriment. The name is derived from the Latin word bruma, meaning “shortest day” or “winter solstice”.
Sol Invictus (“the undefeated Sun”) or, more fully, Deus Sol Invictus (“the undefeated sun god”) was a religious title that allowed several solar deities to be worshipped collectively, including Elah-Gabal, a Syrian sun god; Sol, the god of Emperor Aurelian; and Mithras, a soldiers’ god of Persian origin. Emperor Elagabalus (218–222) introduced the festival of the birth of the Unconquered Sun (or Dies Natalis Solis Invicti) to be celebrated on December 25, and it reached the height of its popularity under Aurelian, who promoted it as an empire-wide holiday. With the growing popularity of the Christianity, Jesus of Nazareth came to be given much of the recognition previously given to a sun god, thereby including Christ in the tradition.
There seems to be an incredible cultural history represented in this one day (or collection of days*): religions rising, co-existing, merging, superseding others and, ultimately, being forgotten; on top of the ancient yet continuing importance of the shortest day and alongside countless non-religious influences (e.g. Dickens, Prince Albert, Thomas Nast). I have a new-found respect for Christmas!
There are so many gods and festivals - from all around the world - to choose from at this time of year but personally I look forward to putting the Bacchus back into Christmas.
* For another complication:
In the early-to-mid 4th century, the Western Christian Church first placed Christmas on December 25, a date later adopted also in the East. The original date of the celebration [of Jesus’s birth] in Eastern Christianity was January 6, in connection with Epiphany, and that is still the date of the celebration for the Armenian Apostolic Church and in Armenia, where it is a public holiday. As of 2011, there is a difference of 13 days between the modern Gregorian calendar and the older Julian calendar. Those who continue to use the Julian calendar or its equivalents thus celebrate December 25 and January 6 on what for the majority of the world is January 7 and January 19. For this reason, Ethiopia, Russia and Ukraine celebrate Christmas, both as a Christian feast and as a public holiday, on what in the Gregorian calendar is January 7.