No, December 25th was not a calendar date prior to Caesar ...

Q

If the Romans were originally the ones to create the calendar year, what did the very ancient civilizations use before them?
https://www.quora.com/If-the-Romans-were-originally-the-ones-to-create-the-calendar-year-what-did-the-very-ancient-civilizations-use-before-them/answer/Hans-Georg-Lundahl-1

Answer requested by

Marc Bloemers

Hans-Georg Lundahl

just now

none/ apprx Masters in Latin (language) & Greek (language), Lund University

They used other calendars.

The Greek one is close to the Hebrew one. So was the Roman up to Caesar, but more clumsy and left to abandonment between Punic Wars and Caesar. 12 months all years, but a 13th month some years, somewhat less often than every second year. Months were lunar.

Probably, some calendars, like the one of Romulus and the pre-Christian Norse, but this is speculative, counted months only over non-winter, and had a winter leave between counting months next year - in this case the winter leave would have varied between two and three months for earliest calendar of Rome.

Babylon had 360 days each year, precisely as Muslims have 12 lunar months each year, no leap years, and for Babylon the months were all of 30 days. In Egypt also you had 30 days times twelve, but you also had five non-month days, which were making the rotation of the year around the seasons slower. They did not have leap years.

Yeah, I know, December 25th was not mentioned in the question, but it is arguably about the claim Nimrod'd birthday was "December 25th". Indirectly./HGL