Comment by rfwhyte

We do know pretty much exactly when they pyramids were built though, (+/- a couple hundred years, which in this context is "Exact" enough) as there have been numerous carbon datings of organic material found in the mortar between the stones of the pyramids, which all broadly line up with the other textual evidence (Mehrer texts, etc.) and contextual evidence (Dating of the work camps surrounding the pyramids) and there really isn't any great mystery in how they were built either, just a lack of specificity in terms of what exact method was used (ie. was it an internal or external ramp, were pulleys used, etc.)