Christmas makes no sense, and we’re not just talking about that time David Bowie and Bing Crosby collaborated on a festive sing-along. No: the basic facts of the annual ritual just seem to defy logic and meaning. What do brightly lit trees and mistletoe have to do with the birth of a prophet in Bethlehem thousands of years ago? What does a jolly, portly man in red and white garb have to do with Christianity? What’s the meaning behind the Yule log? And just what kind of a name is Noddy Holder anyway? (The latter question probably defies all historical analysis.

Many people have a general inkling about the way old pagan traditions and celebrations fed into Christmas as we know it today. But the details – which are still debated by experts, as they reach far, far back into the mists of time – are fascinating and surprising

Jesus’ birthday

Scholars have argued about the exact year and date of Jesus of Nazareth’s birthday for a long, long time. These arguments can get incredibly nerdy and forehead-clutchingly complex, involving the kinds of Biblical code-breaking and cunning conjecture which would make Dan Brown proud. Take the whole issue of the Star of Bethlehem, which shone so brightly and led the wise men, or 'Magi', to the infant Christ. There have been numerous interpretations of what the Star really was, and what its appearance can tell us about the timeline of Christ’s life. A paper published by an astronomer back in the 1990s, for example, suggested it was actually a comet which had been observed by other sources in the year 5 BC.

Or maybe the Star of Bethlehem was actually the light cast by the alignment of the planets Saturn and Jupiter, which occurred in October a few years previous to that? Others contend that September was the actual birth month, getting this from calculations involving John the Baptist’s father. Why? Well, according to the Bible, he was at work one day when he was approached by an angel and told that his wife was to have a baby. Six months later, the Virgin Mary was given similar celestial news about her own pregnancy. Now, the thinking is that since John’s father was a certain kind of priest who according to historical sources would have practiced in June, then Mary must therefore have conceived in December, and given birth to Jesus in September. Of course, others have suggested varying dates for when John’s father would have been attending to his priestly duties, and there’s really no way of telling for certain. Aside from all that, it’s been more generally pointed out that, as shepherds were tending their flocks when Jesus was born, it’s more likely to have been spring rather than winter. There’s also the bit in the Bible reporting a census being carried out on the citizens of the Roman Empire at the time of Christ’s birth; some believe it’s unlikely the Emperor would have sent his man out to collect the census information in the dire weather of winter. To which others might point out that the Roman Empire’s HR department probably wasn’t too fussed about the comfort and well-being of their staff, so it may well have been winter after all.

Bottom line: nobody knows when Jesus’ birthday was. Except that it almost certainly wasn’t December 25th. So why that date? Some devout Christians have attempted to use the wording of the scripture (including the variations on the John the Baptist timeline above) to justify December 25th as the actual birthday. But the more generally accepted thinking is that pagans were indeed the people whose winter celebrations paved the way for our yearly Secret Santa indecision and Christmas pudding heartburn. Thanks, pagans.

Merry Saturnalia and a happy Sol Invictus day

The most obvious precursor was the wild and madcap Roman festival called Saturnalia. Running for several days in early to mid-December, and held in honour of the god Saturn, this has become one of the most notorious shindigs in history, and with good reason. Never mind board games, charades and kipping on the sofa at 4pm – the Romans marked the winter festivities with raucous parties, rampant gambling and turning all social norms upside down.

This even meant servants and slaves were allowed to take control, with their masters even serving them feasts and following their orders. They were also allowed to openly criticise those in power, making Saturnalia an annual flowering of free speech and cheeky satire. All in all, Saturnalia had all the hype and excitement we associate with Christmas today. As the Roman writer, Seneca reported, “It is now the month of December, when the greatest part of the city is in a bustle… Loose reins are given to public dissipation, everywhere you may hear the sound of great preparations'. Interestingly, the festivities also saw houses decked out in greenery, and gifts were exchanged. Saturnalia is a classic example of a winter solstice festival, one of many which have evolved in different cultures to bring good cheer in the season of long nights, and to mark the sense a sense of renewal and rejuvenation. In 274 AD, long after Saturnalia was already a thing, the Romans established yet another way to mark the season: a day to celebrate the sun god Sol Invictus. And the day in question? December 25th.

By this point, Christianity was already a burgeoning religion, and within a handful of decades, Constantine the Great would officially adopt it as the religion of the Roman Empire. Early Christians would have freely shared in the good times of these pagan festivals, as a Christian scribe would write several centuries later:

'It was a custom of the Pagans to celebrate on the same December 25 the birthday of the Sun, at which they kindled lights in token of festivity. In these solemnities and revelries, the Christians also took part.' Less than a century later, Pope Julius I officially established that same date as Christ’s birthday, conveniently appropriating the existing pagan shenanigans as a key Christian date.

The Vikings have their say

But joining the dots between Saturnalia, Sol Invictus and Christmas doesn’t tell the whole story. An equally important influence on our festive rituals today came from other parts of Europe, particularly the Germanic and Nordic peoples. The word 'Yule', for example, derives from a Viking festival which was held to encourage optimism and good luck during the depths of winter.

The saga goes onto to say that, 'Before that, Yule was celebrated on midwinter night', and that the king 'coaxed those who were dearest to him into becoming Christians'.

According to one of the best-known Viking sagas, Haakon the Good, the 10th Century King of Norway, deliberately used the Yule celebrations to smuggle in the Christian faith. Having been raised as a Christian in England, Haakon practised his religion in secret because “the land was altogether heathen and much idolatry prevailed'. However, he 'established in the laws that the Yule celebration was to take place at the same time as is the custom with the Christians.' In other words, turning it from a solstice festival into a celebration of Jesus. The saga goes onto to say that, 'Before that, Yule was celebrated on midwinter night', and that the king 'coaxed those who were dearest to him into becoming Christians'. Read more about: Ancient History 8 forgotten Christmas traditions of the UK by Sky HISTORY

The Yule log itself is a relic of those long-lost days. Although today we tend to think of it as a big, cakey confection to stuff into our faces in the rare moments we’re not gorging on mince pies and Quality Street, Yule logs were originally real, actual logs. Its origins are obscure, but we do know it was traditionally burnt on a fire and was said to bring good luck. Mistletoe is another emblematic reminder of the pre-Christian traditions of the region. This parasitic plant is an unlikely symbol of romance and Christmas courtship today, and its importance in winter festivities is said to stem back to a Norse myth involving the infamous trickster god Loki. As the story goes, another god called Baldr was driven to paranoia by visions of his own death. His mother, the goddess Frigg, made every earthly object vow never to harm him. As a result, Baldr became known for his invincibility – until Loki turned up and fashioned a weapon out of mistletoe, the one thing which hadn’t made the vow. Baldr was killed, and Frigg’s tears of woe were caught on the mistletoe’s branches, turning into the white, pearl-like berries, symbolising her love for him. Remember that story for the next time you find yourself stuck making awkward flirtatious small talk underneath a clump of mistletoe at a party.

As for the most famous symbol of the festive season, the Christmas tree… It’s possible this is a descendant of the evergreen ornaments used by both Roman revellers during Saturnalia, and traditions of tree worship during winter solstice rites in other pagan cultures, in which the evergreen represented new life in the midst of darkness and despair.

Other celebrations of the season

Such is the significance of the winter solstice, and the long, ominous nights of winter in general, that a glittering variety of festivals have sprung up across countries and cultures. One interesting example is the Jewish Hanukkah, which – unlike other winter festivals like Christmas – has a tangible historical reason for being marked during this part of the year.