when was the Mayan calendar conceived?

Factual Questions
1

I get a pretty wide range of dates for Mayan culture, depending on whether we’re talking “Preclassic” or what. See Wikipedia for a basic outline.

But I’m trying to determine when the calendar was dreamed up (roughly). The impetus is the trailer for the movie 2012 which is based on the famous Mayan calendar’s last date. Said trailer says “Mankind’s earliest civilization predicted it…”

I flatly don’t believe the Mayans were mankind’s earliest civilization or even close. But to refute that, wihtout just mouthing off like an idiot, I need to decide on a time for the “Mayan Civilization,” either the Late Mayans or the Preclassic or some point in time – and of course the most useful timeframe would be whatever period the Mayans developed their “long calendar,” if such a thing is even knowable.

2

Even the oldest dates given by the wikipedia article are considerably later then the earliest dates fo the beginnings of civilizations in Mesopotamian and Egyptian, so Mayan culture (and thus, presumably, their calander) certainly isn’t the oldest human civilization (indeed, I don’t think it’s even the oldest MesoAmerican civilization)

3

The four oldest civilizations in the world are the Mesopotamian, Ancient Egyptian, Indus Valley, and Chinese. All well predate 2000 BC.

I’m going by possibly-faulty memory here, but I’m reasonably sure that the last time we did this in GQ, we came up with the Egyptian civilization being a hair older than the Me4sopotamian, and both significantly predating the other two.

Nothing in the New World even comes close.

4

One of the reasons given by the Ancient Mayan Secrets ™ crew is the quite true statement that the Mayan calendar has a base date of something like 4600 BC (in the Mayan dating system, of course – the equivalent of “January 1, year 1, cycle 1, era 1” more or less). However, that’s almost certainly a ‘picked’ date to fit some symbolic astronomical connection or other numerically important point, not a “real” date – approximately equivalent to the Julian day 1 which was purposely set before anything anyone at the time Scaliger did his calculations could possibly want to write a date for.