We have a thing called "Three Kings" (aka. "three wise men") in Poland, that falls on Jan 6th. If My Math Is Correct™, there's 12 days between the Christmas day (Dec 25th) and Jan 6th, so maybe the song is about this period?

Epiphany (GP had a typo) and Three Kings is the same occasion, in fact. Wikipedia: https://en.wikipedia.org/wiki/Epiphany_(holiday)

Yes, and I would be glad to see such a shift.

Shakespeare is still being read, I think.