Egyptian pyramids
Contenido
En el periodo de las primeras dinastías del Antiguo Egipto, los poderosos que disponían de bastantes medios económicos eran enterrados en unas estructuras de base rectangular, techo plano y muros laterales inclinados denominadas mastabas.[10][11] Posteriormente está documentada la construcción de un tipo de pirámide atribuida al arquitecto Imhotep, que diseñó el que los egiptólogos consideran que es una tumba para el faraón Zoser. Imhotep se considera que fue el primero en concebir la idea de apilar las mastabas, llevando a cabo la creación de un edificio compuesto por una serie de escalones conseguidos con la disminución de la medida de la base hacia el ápice; el resultado fue la pirámide escalonada de Zoser, que fue diseñada para servir como una escalera gigantesca mediante la cual el alma del faraón muerto podía ascender hacia los cielos. Fue tal la transcendencia de los éxitos de Imhotep, que posteriormente fue deificado por los propios egipcios.[12].
La mayoría de las pirámides descubiertas en Egipto fueron construidas como tumbas para los faraones y sus consortes durante el Imperio Antiguo y el Imperio Medio.[13][14] La Gran Pirámide de Guiza, construida por Keops (Jufu), es una de las Siete maravillas del mundo antiguo y la única que ha sobrevivido hasta nuestros días.
Symbolism
Although there is general agreement that the pyramids were funerary monuments, there is disagreement about the theological principles that could have framed this functionality. One theory states that it could have been designed as a kind of "resurrection machine."[15] The Egyptians believed that the dark area of the night sky, around which the stars appear to revolve, was the physical entrance to the heavens. One of the narrow shafts extending from the main burial chamber through the entire body of the Great Pyramid points directly towards the center of this part of the sky, suggesting that the pyramid may have been designed as a means of assisting the soul of the deceased pharaoh on its journey to the residence of the gods. All the pyramids of Egypt were built on the west bank of the Nile, since in Egyptian mythology the sunset was associated with the kingdom of the dead.[16].
The pyramids rose to the sky and helped the pharaoh, considered a divine being, when he left the earth to facilitate his return to the home of the gods, the place from which he had come. For this same reason, the Egyptians believed that the body had to be preserved and prevented from being corrupted, which they achieved through a very elaborate method of embalming. Right in the center of the pyramid was the tomb, usually made of stone, and around the mortuary chamber there were writings with spells and incantations to facilitate the movement of the dead to the other world. Not only was it important to preserve the body, but there needed to be a sculpture with his bust that was placed inside the chamber without anyone seeing it; Thus the magic worked and the soul could revive. The Egyptians called sculptors "he who keeps alive."[17].
Construction system and types
Some pyramids were not simple collections of stone, since their construction required skill, ingenuity, organizational capacity and a large amount of labor. Although some civilizations, such as the Egyptians, already knew the discharge arch, they preferably used voussoir structures. However, the large stone lintels could not withstand the strong pressures exerted on them without fracturing, so to open interior rooms and corridors they resorted to the false vault technique, an architectural solution consisting of slightly and staggered approximation of the courses of the walls; This had to be done until an effect similar to that of a pointed arch was achieved, but with horizontal voussoirs. Although all the pyramids had the same square base and the same diagonals that rose towards the upper central point, archaeological studies have shown that each one presented different interior construction variations, due mainly to how the central core was built.[18].
The absence of documents has not allowed us to know the construction methods used in the construction of the ancient pyramids but, since there is no evidence of the use of the wheel, the most accepted theories lean towards the use of ramps or external spirals on which the blocks would be made to slide using levers.[19][20].
The exterior covering of these buildings varied greatly from one culture to another and everything from limestone coatings to stuccos have been found. The inner core could be made up of layers of stone and mud - which were inclined inside the pyramid -, by rubble of stones within load-bearing walls, or by bricks.[18]] Over the years, the stones that covered the exterior were used in other constructions, so the inner core was left outdoors, exposed to the outside elements, degrading and eventually being destroyed.[18].
Orientation
The faces of the pyramids are oriented in the direction of the four cardinal points. Already in the Old Kingdom they oriented themselves in a very precise way, a fact that can be observed in the layout of the Great Pyramid of Giza, in which the greatest deviation that has been found is 3'26" of arc. The Egyptologist I. E. S. Edwards considered that this precision could only have been achieved thanks to extensive astronomical knowledge, with calculations made taking into account the arrangement of the stars.[21] Another theory proposes that it could have been calculated by observing the Sun when it rises. and when it sets, measuring the equal but opposite angles from the north. This method is based on the placement of a stake with a vertical plumb line and its shadow is measured about three hours before noon, so the length is the radius of a circle; the shadow moves until it reaches the end of the circle and forms a right angle with the previous line of the noon shadow and in the bisection of the angle the north is found. solstices.[22].
To obtain the characteristics of a quadrangular pyramidal body, several squares are created alternately, one on top of the other, always decreasing their measurement proportionally. This geometric calculation, which seems simple, when it has to be carried out on a monumental scale requires great precision, since with just a small deviation in the diagonals, the cusp would be off-center. The Egyptian builders had a measurement called the Egyptian royal cubit (mḥ nsw) which is about 52.4 centimeters, and they could obtain the slope by measuring units of height and base. For the inclination of Cheops' pyramid, it would have had to measure 14 units upwards and 11 inwards.[23].
Pyramidion
The pyramidion is the stone piece with a quadrangular pyramidal shape that was located at the highest part of the obelisks and pyramids. It symbolized the place where the solar god Ra "Ra (mythology)") or Amun was located, at the top of the monument, at the junction between Heaven and Earth. The pyramidion was usually made with materials such as Tura limestone "Tura (Egypt)") - for example the Red Pyramid of Seneferu (Dynasty IV) -, or black granite - such as that used in the pyramid of Jendyer (Dynasty XIII) -. This piece was generally covered with gold, bronze or another metal alloy to make it shine when sunlight fell on it.[24].
The pyramidion of the Black Pyramid of Pharaoh Amenemhat III, discovered in 1990, is located in Dahshur, about 40 kilometers from Cairo. On one of its faces it has an engraving of a winged solar sphere sculpted in relief and below there are two sacred eyes that represent the eyes of the pharaoh who is looking at the sun from inside the pyramid; Under them there are three signs engraved that mean nefer (perfection or beauty), as well as a hieroglyph with the name and title of the pharaoh.[24].
Quarries
The first pyramids were built of stone and it is assumed that all of them had a quarry nearby to supply the main material; For example, the Giza quarry is located about three hundred meters from the Great Pyramid and there is a large horseshoe-shaped cavity about thirty meters deep. The white limestone needed for the final coating comes from Tura "Tura (Egypt)"), a town that was near modern-day Cairo. Other materials that were used were granite, which was brought from Aswan, basalt and gypsum "Gypsum (mineral)") from Fayún, or copper, transported from Sinai.[25].
In the quarries there are large, wide and deep channels; It is believed that they needed to make them due to the lack of iron tools, because when tools made of this material are available, the channels that open near a block to be extracted are hammered with iron wedges until the desired block cracks underneath. In those days, workers had to use large wooden levers to separate the blocks, so they needed more space due to the passage channels necessary to maneuver. In the quarries of Tura, where there was high-quality limestone, workers opened tunnels beneath the first layers, creating a kind of gallery where they could dig to obtain the stone.[26].
Tools used
To extract granite from the Aswan quarries, channels were opened using diabase hammers. This technique is well referenced, since large quantities of mallets have been found in the quarry itself. According to the American archaeologist and Egyptologist Mark Lehner "Being sent to (the) granite quarries was, without a doubt, being condemned to the most miserable of the jobs of the pyramid builders."[27]
The process of cutting the stones was extremely slow due to the great hardness of the granite stones. To work them, bronze and flint tools were used and polishing was achieved by rubbing with the same powder from the stones or with harder abrasives such as quartzite powder.[28].
Supplies and transportation
Another material that was needed in large quantities was wood, used as fuel for the fire in the forges and to make tools, as well as for the ovens where bread was made, a basic food for workers. Infrastructure was also needed to supply other types of food, such as cereals, fish and meat. Fuel and food were transported in small boats, ships of which numerous representations survive in the reliefs of the tombs of the Old Kingdom.[25].
Transportation across the Nile was an essential means of communication for the ancient Egyptians; They had ships adapted to all types of loads, as can be seen in a scene from a relief of the Pyramid of Unis. Once unloading was completed, transportation by land was carried out using animal traction, but also by means of a large workforce dedicated to the action of dragging the materials; This has been recorded in several reliefs. The lack of a wheel suggests that they were helped by a type of sleigh.[29].
Ramps
The studies carried out to find out what kind of ramps were used to make the construction of a pyramid possible have given rise to multiple theories. Perhaps they used a straight ramp leaning against one face of the work, but here several options open up because it could be that they needed to occupy an entire face of the pyramid or just a part of it; In this second case, the ramp would need to be very narrow and of the necessary height to reach the end of the pyramid. Furthermore, to maintain an adequate slope it would have had to be developed as the construction was being built.[30].
Another option could be a spiral-shaped ramp that surrounded the pyramid and ascended over the courses of the step pyramid when it had not yet been covered with the last layer of stone. However, tests carried out on the north face of the Pyramid of Mycerinus showed that, at least, the unfinished faces were not stepped and therefore did not make this type of ramp possible. Another similar theory presents a zigzag ramp made on one face of the pyramid but which presents almost the same problems as the spiral ramp.[30].
List of Egyptian pyramids
Until 2008, some 140 pyramids had been discovered in Egypt.[31][32] Among the most important are: