Nostradamus' works have not EVER been interpreted well enough to be able to date. Whatever coffee-table books you read this info in, (or worse, internetsite), it's false. I happened to read his poems for making an essay, and the only thing that struck me was that he named 'hitler' by the name of 'hitser' or 'hister', but that still doesn't prove anything seeing as how THERES NO DATE MENTIONED ANYWHERE to accompany his poems. Let's not forget hitler wasn't always named hitler, maybe, since he was into the occult, was influenced by this and changed his last name from schicklegruber (or something like that) to hitler. So it's remarkable but by no means proof of predicting anything.
All date predictions are based on alchemical and astrological systems, very shady, very open to interpretation by pseudo scientists.
Also the mayans were wrong about the time of their creation, why would they be right about the end of it? They claimed their civilisation would end about now, but it has been killed by a handfull of conquistadores hundreds of years ago.