We do have kings lists compiled by the Greeks. But our primary source of dating is through radio-carbon dating. In addition to actual timbers used to support galleries within the pyramids, there are also large ash piles where the workers stoked furnaces to bake the gypsum to make mortar for the pyramids.

Inside the pyramids there is also a lot of fill material some of which was apparently recycled from former monuments. So leftover inscriptions on that was used to create older bounds on ages. If Djoser’s name is found on recycled materials, the new building must be younger than Djoser.

Similar testing has been done on the workmen’s villages. Testing on rubbish piles and materials that composed the buildings in the workmen’s villages also shows dates that agree with that in the pyramids themselves.

So we have a pyramid. The texts say it was built by Menkaure, and gives us dates for Menkaure. Carbon dating on the interior timbers agree with the dating, as do dating from the fire pits, rubbish piles, and support buildings. So we’re fairly confident that the dating is largely accurate.

Not every monument or tomb is that well documented and studied. But we’re fairly confident about the dating three pyramids in the Gaza complex.

This was drawn primarily from Dating the Pyramids Archeology Volume 52 Number 5, September/October 1999 by members of the David H. Koch Pyramids Radiocarbon Project