Yeah, I’m not sure.

I vaguely remember Hammurabi’s code from ancient Babylon dated at least a thousand years before Zoroastrianism came on the scene, but most of the religions at that time were polytheistic, which is what made Zoroastrianism unique. Still, I thought the archeologists discovered calendars written in Hebrew back then, too. And I wouldn’t be surprised if there was some lesser-known (but no less ancient) Egyptian religion that’s still worshipping a Sun God, exclusively. But, I could be wrong.