A mastaba (//, or //) or "pr-djt"[pronunciation?] (meaning "house for eternity" or "eternal house"), is a type of ancient Egyptian tomb in the form of a flat-roofed, rectangular structure with outward sloping sides that marked the burial site of many eminent Egyptians of Egypt's ancient period. Mastabas were constructed out of mud-bricks (from the Nile River) or stone. In the Old Kingdom, kings began to be buried in pyramids instead of mastabas, although non-royal use of mastabas continued for more than a thousand years.
The greatest stimulus for the ancient Egyptians was their belief in an afterlife. This was reflected in their architecture and most prominently by the enormous amounts of time, money, and manpower involved in the building of their tombs. "Egyptians believed that the soul could live only if the body was preserved from corruption and depredation." From the predynastic era forward, the ancient Egyptians strove to develop methods for preserving the bodies of the dead. Initially embalming methods were used, and later architectural tombs were devised to preserve the corpse indefinitely. The body would be placed in a deep, sealed chamber such as a mastaba. The remains were not in contact with the dry desert sand, consequently natural mummification of the remains could not take place. In order to preserve the remains, the ancient Egyptian priests had to devise a system of artificial mummification.
The word Mastaba comes from the Arabic word for a bench of mud, likely because when seen from a distance it resembles a bench. Inside the mastaba, a deep chamber was dug into the ground and lined with stone or bricks. The exterior building materials were initially bricks made of sun dried mud which was readily available from the Nile River. Even as more durable materials of stone came into use, the cheaper and easily available mud bricks were used for all but the most important monumental structures.
The above-ground structure was rectangular in shape, had sloping sides, a flat roof, was about four times as long as it was wide, and rose to at least 30 feet in height. The mastaba was built with a north-south orientation. This above ground structure had space for a small offering chapel equipped with a false door to which priests and family members brought food and other offerings for the soul of the deceased. A second hidden chamber called a "serdab" (سرداب), from the Persian word for “cellar,” housed a statue of the deceased that was hidden within the masonry for its protection. High up the walls of the serdab were small openings. These openings “were not meant for viewing the statue but rather for allowing the fragrance of burning incense, and possibly the spells spoken in rituals, to reach the statue.”
Architectural evolution 
The early known mastaba’s are at the great cemetery at Saqqara. Mastaba’s are improved burial structures of tombs from the grave mound of the predynastic period. And the earliest mastab’s are believed to be from the first dynasty at Tarkhan, and were simply covered open pits. There were some differences between the pre-dynastic graves and grave from the first dynasty, but the only differences were with items that were enclosed within the tombs. Early mastabas were short oblong structures with two offering areas, and open air chapels.  These early mastaba’s from the First Dynasty, were crude brickwork with the use of the Egyptian way of bonding, which was introduced around the accession of Menes or earlier. This form was a better protection for the structure with it being brick-lined and they had wooden roofed substructures, which gave the grave a more durable structure. The exterior of the mastabas were nearly straight and vertical, only a five degree angle.  A superstructure of Zer, improved mastabas is a structure of adding layers of brickwork around the base. Then the Zet Pyramid, a structure followed the form of Queen Neithhetep tomb, wife of Menes but sunk into the ground. The layered mastaba lead to the step form pyramid of stones, the Step-Pyramid of Djoser.  The Step Pyramid was built by Pharaoh Djoser, who began to build it as a traditional mastaba. It was made from stone, which by the end of his 19 years as Pharaoh; it became a six stepped layered mastaba. It’s known to be Egypt’s first pyramid and the largest of its time to have been built. Given credit to this great structure was chief architect, Imhotep. Imhotep was a great architect who figured a way to structure the stones into a great architect of his time. The Step Pyramid of Djoser is enclosed by a 30 foot wall that included courtyards, temples, and chapels covering closely to 40 acres. Pharaoh Djoser’s burial chambers are underground, hidden in a maze of tunnels.  Then by the first king of the Fourth Dynasty Pharaoh Snefru built his burial, which was influenced by the Step Pyramid of Djoser. This pyramid, Maidum Pyramid, was different than any other previous pyramids built. It’s known to be the first Egyptian pyramid with an above ground burial chamber. The structure of this pyramid represents the efforts to raise the chamber to be closer to the sun god. And another unique part of this pyramid was the interior structure of archlike walls within the burial chambers, which could have been accessed through a slopping shaft. Then at a sudden change, Pharaoh Snefru decided to move and abandoned the Maidum Pyramid for 15 years.  Pharaoh Snefru relocated to Dashur and attempted to build his second tomb. This had two chambers with separate entrances. As the structure of the pyramid was being built, a miscalculation or lack of stability lead the upper half to bend or change angle, thus getting the name as the Bent Pyramid. This structure is considered to be the first attempt at the classic shape of a pyramid we now know today. Due to the structure, Pharaoh Snefru ordered for a third pyramid and sent workers to finish his first pyramid Maidum. The third pyramid of Pharaoh Snefru, the North “Red” Pyramid, is a single burial with two smaller chambers. Among all three pyramids built by Pharaoh Snefru, no one really knows where he is truly buried, but led to believe he may have been buried in his third, North “Red” Pyramid and is known to be the first “True” pyramid to have been built. The Red Pyramid sets the structure for future pyramids. 
|Wikimedia Commons has media related to: Mastabas|
- Hamlin, Talbot (1954). Architecture through the Ages. New York: Putnam. p. 30.
- Badawy, Alexander (1966). Architecture in Ancient Egypt and the Near East. Cambridge: MIT Press. p. 46.
- Ancient Egypt and the Near East. Cambridge: MIT Press. 1966. p. 7.
- Gardiner, A. (1964). Egypt of the Pharahos. New York: Oxford University Press. p. 57 n7.
- R., C. L. (1913). "A Model of the Mastaba-Tomb of Userkaf-Ankh". Metropolitan Museum of Art Bulletin 8 (6): 125–130. JSTOR 3252928.
- Bard, K. A. (1999). Encyclopedia of the Archaeology of Ancient Egypt. New York: Routledge. ISBN 0415185890.
- Arnold, Dorothea (1999). When the Pyramids were Built: Egyptian Art of the Old Kingdom. New York: Metropolitan Museum of Art. p. 12. ISBN 0870999087.