From early in the 3rd millennium BC the pharaohs and their nobles are buried beneath mastabas (see Egyptian burial customs). These rectangular flat-roofed buildings, made of mud brick, cover the burial chamber. They also contain the supplies of food and other items which will be needed in the next world.
In about 2620 BC the pharaoh Zoser entrusts his chief minister, Imhotep, with the task of providing a royal tomb which is out of the ordinary. Imhotep builds a mastaba of stone (in itself an innovation) and then places on top five successively smaller rectangular mastabas. In doing so he creates the first pyramid - the 'step pyramid' of Saqqara.