It is paradoxical that the huge pyramid-shaped tombs upon which enormous resources and energy were lavished finally constituted the principal danger from which the king’s body and its funeral procession had to be protected. The need to provide rooms situated in the core of the monument greatly contributed to research into, and the development of, various structures which would prevent the walls from yielding under the pressure exerted by hundreds of thousands of tons of material.
When the day came when Pharaoh asked them to create a funerary chamber within his future pyramid, his architects had to develop innovative techniques for roofing it on a scale never seen before.
It was in the reign of Sneferu, at Meidum, that the stone corbelled vault was used for the first time to protect the funerary chambers. This process, which consisted in covering a space by a succession of masonry courses slightly overhanging one another, gradually reduced the vault span until it could be crowned by a flat ceiling. This same pharaoh had two other pyramids erected at Dahshur in which this technique reached its peak.
The corbelled vaults of the Red Pyramid (North Dahshur) are incomparably majestic (see left). Their still-perfect condition shows how the masonry elements were carefully and accurately laid. The ceiling of the funerary chamber rises to nearly 15 metres. That of the lower chamber of the Bent Pyramid (South Dahshur) rises to more than