Here's something I got from Channel 4's Time Team.
Durrington Walls is the largest prehistoric henge in Britain.
Archaeologists digging at Durrington Walls have found rubbish pits full of pig bones.
Pigs farrow in the spring. These pigs had been slaughtered at nine months old. Ergo the people at Durrington Walls were in the habit of enjoying a slap-up pork dinner at the Winter Solstice.
"Jesus is the reason for the season"? Only if you accept that "Jesus" is just another name for the Sun.