Ruth A. Johnston, independent scholar, writer and former teacher, posted on her blog All Things Medieval on 20.12.13:
“When Pope Gregory first sent Latin missionaries to the outer northern wilds of Europe, he instructed them to make it easy for converts. If they were used to gathering on a hilltop somewhere on a certain day, find a saint’s day that might be celebrated by gathering on a hilltop. If they have a spring festival, tell them to do the same things in honor of a saint or of Jesus’s resurrection. Build wooden or stone churches near where their pagan shrines were, since that’s where they are used to going. Try to adapt, not buck, the culture. Today we call this “syncretism,” the blending of religious traditions.
Christmas was one of the chief syncretist holidays. Germanic people had a long tradition of burning a Yule log for 12 days in midwinter. They kept a feast in the darkness after the solstice; they often roasted a whole boar. The boar may have been on the menu because it was a big, tasty animal that could be more easily hunted with spears in the snow, or it could have had some religious significance, since each of the gods had a totem animal. Yule was a celebration of life in the time when winter seemed dark and cold, so they always went out to collect evergreen branches as home decoration. Pines, holly and ivy were seen as symbols of defying the cold, remaining green and alive.
Around the time Latin missionaries went north, Dionysius Exiguus (also known as Dennis, like the Monty Python peasant) drew up an authoritative calendar for calculating Easter. The calculation of Easter was hugely controversial in the early centuries and still splits Orthodox from Catholic tradition; in those days it split Ireland from England and one monastery from another. Dennis also marked the day of Jesus’ birth into the calendar: December 25, according to tradition and his calculations. So the Latin missionaries had a newly authorized holiday to provide to the Franks and English.
The four weeks before December 25 were proclaimed a holy fast, the Fast of Advent. During fast days, they were supposed to avoid all animal products, though sweets (if they existed) and alcohol were okay. December 6 arrived about one week into the Advent fast; it was St. Nicholas’ Day, a feast amid the fast. Not surprisingly, it was played up. Cooks had saved up just enough meat and eggs to keep for a week, and they were ready to cook up a big feast to use them up. This is one way that Jolly St. Nick became prominent in the December calendar.
In Charlemagne’s time, Christmas meant a huge feast that lasted several days. Since it was cold, cooks had been able to save up meat, milk and eggs. Men went boar hunting as they had always done, and they found a huge, thick log for Yule. Women and children gathered evergreens to decorate the house. The Latin church calendar had a series of Advent readings and customs to remind everyone of what it was all about.
On Christmas Eve and Christmas Day, the king and his nobles attended the bishop’s Mass. That was the religious celebration.
Charlemagne would have had a really sumptuous feast. Germanic chiefs had always thrown feasts for their men; drinking the horn cup as it was passed around was a constant renewal of the vow to be loyal to the chief who gave the feast. So Charlemagne, as a Christian, invited to his feast everyone who needed a loyalty booster shot. His estates provided bread, fruit, honey, wine, ale, cheese, eggs and roasted fowl. Hunters brought in deer and boar; the knights themselves may have gone boar-hunting with the professionals. It’s likely that several sheep and oxen were also roasted. Cooks had probably spent a week doing advance preparation, such as brewing ale, while woodcutters had been bringing firewood for weeks.
Halls were still heated by a central fire in a pit, with the smoke making its way out a smoke hole in the rooftop, in 800. Tables and benches crowded around the pit where the Yule log, perhaps soaked in alcohol to burn longer, smoldered for twelve days.
In 800 AD, Charlemagne’s Christmas had a special event. The Pope crowned him as Holy Roman Emperor on that day. The title was invented specially for him, but it also projected a vision that the Pope and the King shared: of a new, united, civilized, literate Europe, ready to imitate the glory that once was Rome.”