The shortest day in the year.

It is what old word Yule means.
The English got the word from the Vikings and though we in Denmark today spell the word "jul" or "hjul" it is the same as yule and means wheel - it is the wheel or cycle of the year that is turning and naturally we in the darkest time of year need a good party so already in pre-Christian time we Norse people had the tradition for drinking Yule.

also a celebration of the rebirth of the Oak King, who will warm the frozen earth

@lorne13: True – but that was in the Celtic culture.
The Celts we had here were of course thralls.

@karinaal: lol and they probably weren't very happy about it

@lorne13: About being Celts? No I cannot think they were happy about that.

@karinaal: Thank you, I just learned something new today❣😊

You are welcome and I too am glad that you learned something; then the day is not wasted for any of us.
If I become so old and infirm that I no longer learn something new every day I think I will prefer to die.

@karinaal: I agree❣⭐😊