I spent many Christmasses at the West Saxon court. Christmas is Yule with religion, and the West Saxons managed to spoil the midwinter feast with chanting monks, droning priests, and savagely long sermons. Yule is supposed to be a celebration and a consolation, a moment of warm brightness in the heart of winter, a time to eat because you know that the lean times are coming when food will be scarce and ice locks the land, and a time to be happy and get drunk and behave irresponsibly and wake up the next morning wondering if you will ever feel well again, but the West Saxons handed the feast to the priests who made it as joyous as a funeral. I have never really understood why people think religion has a place in the midwinter feast...Read more here.
Since childhood, I was struck by the contrast between Christmas and the religion that gave the holiday its name. The holiday was fun, and had nothing in common with the worship of a god who was just like the galactic empire, only less rational. I didn't give it too much thought at the time, except to be glad that crucifixion was the furthest thing on my mind around that time and to pity those raised under the evil shadow of religion.
My favorite take on how the Pagan holiday we celebrate in mid winter was stolen by the Christian church is Leonard Piekoff's Why Christmas Should be More Commercial.
But the book I quoted is not primarily about that. It's about the Danes overruning 3 out of 4 Saxon kingdoms in 9th century England, and the Saxon king Alfred who turned that around and created the first unified English kingdom.
Bernard Cornwell is a brilliant author of historical fiction revolving around wars and usually from the infantryman's point of view. You can get a good intro to his work from the BBC Sharpe's Rifles series. The Last Kingdom is my favorite of his so far. After watching and getting hooked on the Richard Sharpe tv series, I picked up The Archer's Tale. I'll eventually read all of Cornwell's books. He's that good.