The earliest form of pyramid, the step, dates back to the 3rd Dynasty, and consists of several steps. A descending passage from the north leads to the burial chamber. Underground galleries surround the pyramid on all but the south sides. The first, and probably the only step pyramid ever completed, is that of King Netjerykhet Djoser at Saqqara. The Step pyramid is not near as pleasing to the eye as the True pyramid, which could explain the quick abandonment of this type of pyramid.
The true pyramid is a natural development and improvement on the step pyramid. The first true pyramids were introduced in at the beginning of the 4th Dynasty. The structure of a True Pyramid is virtually the same as a step pyramid. Packing blocks are stacked until the dimensions were right, and then finishing blocks (usually limestone) were the last touch. The aesthetics are much more pleasing than the step pyramid, but the construction isn't really that different.
A major problem facing the builders of the Ancient Egyptian Pyramids, was that of getting the Large stone blocks to the height they required. the method shown at left, is the only one proven to have been used. The ramps were built on inclined planes of mud brick and rubble. They then dragged the blocks on sledges to the needed height. As the pyramid grew taller, the ramp had to be extended in length, and its base was widened, else it would collapse. It is likely that for the construction of each pyramid, several ramps were probably used..The arrangement of the ramps used for building is in much dispute. Assuming that the step pyramid was built before the outer structure, and then the packing blocks were laid on top, the ramps could have run from one step to another rather than approaching the pyramid face at right angles.
Some of the pyramids indicate an accurate understanding of Pi, but the mathematical knowledge of the Egyptians did not include the ability to arrive at this by calculation. It is possible that this could have been arrived at "accidentally" through a means such as counting the revolutions of a drum.
The internal construction of most true pyramids consists of a series of buttress walls surrounding a central core. The walls decrease in height from the center outwards. In other words, the core of the true pyramid is essentially a step pyramid. The internal arrangement added stability to the structure. Packing blocks filled the "steps" formed by the faces of the outermost buttress walls and casting blocks (often Limestone) completed the structure of the true pyramid.
Architects and builders used a different form of construction in the pyramids of the 12th and 13th Dynasties. Mainly because of economy, for it was suitable for relatively modest structures in inferior materials. Solid walls of stone ran from the center, and shorter cross walls formed a series of chambers filled with stone blocks, ruble or mud bricks. An outer casing was usually added, and although quite effective in the short term, it did not even come close to the earlier construction methods. Pyramids which were built with this structural design are quite dilapidated and worn.
Before the physical orientation and layout of a new pyramid took place, considerable planning was needed under the direction of a "royal master builder". Ultimately, the responsibility fell on the vizier, who was typically the head of all royal works. The first step in the process was taken by specialists who would draw up plans for the pyramid on papyrus. After the construction began, plans and sketches were drawn on papyri or flat slabs of limestone. Planners even made models of their projects, as evidenced by a limestone model of a substructure found in the Pyramid of Amenemhet III at Dahshur. After the planning stage, each step of pyramid building was initiated with foundation rituals.
Pyramids, unlike many other types of religious structures, required strict orientation to the cardinal points. Pyramid alignment may have been carried out through a number of different means, including some methods we have probably never thought of. The primary theory of how the ancient Egyptians oriented most any building that had to conform to true primary coordinates has been by stellar measurements. This involved building a small, circular wall of perhaps mudbrick that had to be perfectly level at the top. Within the circle, a man would stand and through a straight pole with a forked top called a bay, sight a circumpolar star as it rises. A second man at the perimeter of the small circular wall would then "spot" the wall where the star rose. Using a type of plumb line, or merkhet, he would also spot the mark at the bottom of the wall. When the star set, the process would be repeated. Measuring between the two spots would then provide true north from the center sighting pole.
Recently several other theories have been raised, all of which involve some sort of astronomical measurements. A British scholar named K. Spence believes that the Egyptians used two circumpolar stars (Delta Ursae Majoris and Beta Urae Minoris or Epsilon Usae Majoris and Gamma Urae Minors) Another theory set out by a Slovak Egyptologist, D. Magdolen, believes that the ancient Egyptians oriented their monuments using the sun, by means of wooden stakes and ropes. There is in fact a reference in ancient text referring to "the shadow" and the "stride of Ra".
The sun rises and sets in equal but opposite angles to true north. Using a plumb line, a pole would have been set as vertically as possible. Then, about three hours before noon, its shadow would be measured. This length then becomes the radius of a circle. As the sun rises higher, the shadow shrinks back from the line and then becomes longer in the afternoon. When it reaches the circle again it forms an angle with the morning's line. The bisection of the angle is true north. However, this method would be less accurate then the stellar method, but could be fairly accurate during the solstices.
Creating the Ground Plan
After the primary coordinates were determined, the ground plan would be marked out. Some of the methods used to do so varied from pyramid to pyramid. Here, we examine the means by which the ground plan of the Great Pyramid of Khufu at Giza was determined.
Initially, a reference line along true north was constructed from the orientation process. The next step would be to create a true square with precise right angles. Within Khufu's pyramid, there is actually a massif of natural rock jutting up that was used as part of the pyramid's core. Therefore, measuring the diagonals of the square to check for accuracy was impossible.
A second method would have employed the use of a sacred or Pythagorean triangle. The triangles seem to be present in the design of the Old Kingdom pyramids, but there is no real conclusive evidence of their use. Basically, this triangle uses three equal units on one side, four on the next, and five on the hypotenuse to give a true right angle. At Khufu's pyramid a series of holes along the orientation line are dug at seven cubit (3.675 meters or about 12 ft) intervals, so the triangle probably used these positions in the measurement. In other words, the triangle would have been measured as 21 cubits by 28 cubits with a 35 cubit hypotenuse. This would have resulted in a much longer measurement for the perpendicular line then with the use of a set square. If the unites used were any greater, the measurement would have been interrupted by the rock outcrop.
A third method possibly available to the early Egyptians would have been through the use of intersecting arcs. In this method, two circles would have been sketched by rotating a cord around two points on the orientation line. The intersection of the two circles would then provide a right angle. Some doubt this method was used because the elasticity of the string or rope used to sketch the circles would lead to inaccuracies. However, at Khufu's pyramid, there are a number of post holes dug that might have been used to draw such circles, so the method cannot be ruled out. Furthermore, the Egyptian may have used a rod or other device rather than rope or string to draw the circle, eliminating elasticity.
The Platform
An orientation reference line was set up in a larger square by measuring off the established square ground plan. This was done by digging post holes at measured distances from the inner square in the bedrock and inserting small posts through which a rope or string ran. These holes were dug at about 10 cubit intervals. This outer reference line was needed because the original orientation lines would be erased by building work. Various segments of the reference line could be removed so that building material could be moved into place. Then measurements were taken from the guide line as the material for the platform were put in place so that the the platform was in accord with the initial floor plan.
Not only was the platform required to be laid in a perfect square, but it was also required to be very level. In Khufu's pyramid, the platform is level to within about 2.1 cm (one inch). There were several means that this too could be accomplished. Traditional though, apparently originally conceived by Edwards, suggests the use of water to level the platform. He thought that the ancient Egyptians might have built a mud enclosure around the platform that was then filled with water. A grid of trenches would have been cut at a uniform depth below the water. However, modern Egyptologists believe this method would have been cumbersome at best. The platform would have had to have been chiseled beneath the water. Perhaps a more accepted theory involves channels being cut to form a grid within the platform, which was then filled with water. At the top of the water's surface, the level would be marked along the sides of the channels, and then the platform cut accordingly.
Our thinking on pyramids has evolved considerably over the years. Many of us who are a bit older were taught that the pyramids were built using Jewish slave labor, which is a fabrication of immense proportions. Most of the pyramids were built long before the Jews made their appearance historically and currently, many if not most scholars believe they were not built using slave labor at all (or perhaps a nominal number of slaves).
Otherwise, we can also dismiss offhand alternative theories related to aliens or some lost culture being responsible for pyramid building. There is just far too much evidence, including tools, drawings, evolutionary changes, and even worker villages that rule these farfetched ideas obsolete.
However, some mysteries remain, even in some of the best well known Pyramids. The most famous of them all, the Great Pyramid of Khufu, continues, year after year, to give up a few more secrets, and there doubtless remains much to learn from these Egyptian treasures. There may even be one or more pyramids yet to be discovered.
(c)Tour Egypt & The data from the Museum of Antiquities,Cairo
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