Saturnalia was likely not the holiday that became Christmas. Or at least that’s not the complete story.

Part of it is that solstice celebrations were pretty common. Modern Christmas just owes most of its pomp to more Celtic and Norse traditions.

Also, the timing of picking December 25th as Christmas has more to do with a bit of rabbinical superstition than anything else. See, there was this firmly held belief (based on nothing) that great men would die on the date of their conception.

So since Jesus died in late March or early April, he had to have been born nine months later, or at the end of December, Because that’s how the logic went.

And yes, it’s the exact same sort of logic that Monty Python made fun of with the “does she weigh as much as a duck?” scene.