Have you ever heard someone claiming that Christmas has pagan roots? That Christians stole (!) a pagan feast and made it Christian (how dare they!?)?
It's popular #fakenews. No one stole anything from anyone, and nothing was adapted or adopted.
Below are two articles that do some myth busting.
The Myth of the Pagan Origins of Christmas.
This article is by Professor William Tighe, who argues that, actually, the pagans co-opted it from the Christians! Who woulda thunk it?
"...the now-popular idea that Christians co-opted the pagan feast originates with Paul Ernst Jablonski (1693-1757), who opposed various supposed “paganizations” of Christianity."
Full article is here.
Second article is by Father Andrew Stephen Damick, who tries to use logic to show how ridiculous of a claim it is to say that Christmas has pagan roots.
"Supposedly, Christmas is secretly pagan, secretly syncretist, secretly a co-opting of pagan stuff and ignorantly claiming it to be Christian. But the truth about these things is so available that it’s literally staring out at you even from Wikipedia."
Unless otherwise specified, the articles here are posted by Father Aleksey, who has no sense of humor and is extremely straight forward.