Since we're getting into "did you know that Santa's eight tiny reindeer are a reference to the eight legs of Odin's steed?" season once again, remember: while there are some elements of Christmas (or Hallowe'en, or Easter, or...) observations that are probably pre-Christian in origin, before one believes any of that this-is-really-100%-just-a-Pagan-holiday-with-the-serial-numbers-filed-off stuff, one must consider all of the following possibilities:
Our earliest known records of the cited pre-Christian practices were written down by some random Christian monk centuries after the fact, and we genuinely have no idea how accurate this account is, to what extent the apparent similarities with Christian practice are due to the author deliberately or unwittingly putting a Christian spin on it, or indeed, whether they were just making shit up.
The similarities between the two sets of practices have been exaggerated or misrepresented by Christian writers who were bent for prefiguration theology (i.e., the idea that the Bible echoes backwards in time and pre-Christian religious practices were unwittingly imitating future Christian practices).
The similarities between the two sets of practices have been exaggerated or misrepresented by Protestant writers who believe that all Pagan deities are Satan in disguise, so they think that if they can prove that Catholic practices are secretly Pagan in origin, that proves that Catholics are secretly Satanists.
The similarities between the two sets of practices have been exaggerated or misrepresented by overzealous mythographers trying to prove that all mythology and religion throughout all of human history is secretly a single unified monomyth; if it's pre-Victorian, expect shades of prefiguration theology, while if it's post-Victorian, expect a lot of stuff about the Collective Unconscious.
A bunch of 19th Century proto-Fascists were trying to construct a pre-Jewish cultural identity (and considered Christianity to be tainted by association), but didn't want to give up any of the fun rituals, so they made some shit up about how it was still okay to do Christmas because something something Odin, or whatever.
A bunch of early 20th Century Pagan reconstructionists filled in the gaps in their understanding of pre-Christian ritual with culturally Christian assumptions, then turned around and pointed at their own accidentally Christianised reconstructions as evidence that Christian practices are derived from them.
A bunch of late 20th Century self-help manual authors tried to break into the occult bookstore market by uncritically repeating any or all of the above.
Someone on the Internet just made it up.
