Holy SHIT I just read this for the first time. Amazing. Dec 25th isn't Christmas. It's Sol Invictus.
>Sol Invictus ("Unconquered Sun") was the official sun god of the later Roman Empire and a patron of soldiers. On 25 December 274 AD the Roman emperor Aurelian made it an official cult alongside the traditional Roman cults.[2] Scholars disagree about whether the new deity was a refoundation of the ancient Latin cult of Sol,[3] a revival of the cult of Elagabalus,[4] or completely new.[5] The god was favored by emperors after Aurelian and appeared on their coins until Constantine I.[6] The last inscription referring to Sol Invictus dates to AD 387,[7] and there were enough devotees in the fifth century that the Christian theologian Augustine found it necessary to preach against them.[8]
Note that this comes off the heels of Saturnalia which was a weeklong festival celebrating the god Saturn.
Some have credibly theorised that in the ancient vernacular, the Sun = Saturn and most Sun worship is actually Saturn worship.