It literally comes from the Jewish luni-solar calendar, in an attempt to keep it concordant with Passover.

But yeah, like basically every calendar in the history of the earth uses either a lunar, luni-olar, or solar cycle. So basically all holidays, events, and occurrences are going to occur based on one of those calendars. That doesn't mean people were stealing holidays from each other, although sometimes they were. It just means that the planet works the same way for everyone, and there are only so many ways to mark time astronomically when you only have naked eye observation.