Excavations-of the University of Alexandria in the Giza Necropolis during the 1949-50 season have brought to light interesting architectural elements, the most important of which are the vaults and domes. These elements, although mostly known before, present special features which make them invaluable documents for the study of the evolution of early architecture in Egypt.
Between the open court and the vestibule (?) of theMastaba of Nfri, an archway in excellent state of preservation is covered with a flat vault resembling the three-centred arch of Gothic architecture.
From a flat string moulding at 73 cm. above ground springs the vault with span 2.50 metres, height 96 cm. and depth 65 cm. A flat arch of the same type forms the front of an alcove or recess in the chapel of the Mastaba of Sab (G3033) in the Minor Cemetery Cem3000 at Giza.

This one of Nfri however, differs slightly, being opened through and presenting the rare feature of ribs. These are adjacent elements, semi-circular in section, running transversely to the archway axis, from one jamb to the other. The vault shows four ribs and is two bricks deep between the external and internal faces. The bricks are radiating, placed as headers, with their longer side parallel to the axis of the opening. They are of peculiar shape. A special mould had to be used, with one of the long sides (32 cm.) shaped into two adjacent semi-circles.
The arch is only one brick thick (15 cm.). The ribs are plastered over with a thick layer of mud and a coat of mortar, painted in Pompeian red. The plinth is topped with the projecting white flat string and the external and internal faces are covered with whitewash.
Similar ribbed vaults had been found near-by in the Minor Cemetery (G2098, G3024), showing the sameexternal features as to shape, size and colour, but quite different in construction. Fisher, who discovered them, called them » reeded vaults», a name which indicates the origin of their design. Nothing could have led the architect to use such curious features but the wish to transpose the characteristic aspect of the interior of reed vaults and arches into brick architecture.
For some reason, which may be related to artistic conservatism or more probably to religious tradition, such elements of design, originating purely out of the forms of vegetable materials, were considered worth retaining, and adapted to the new material used: crude brick.

The extremely rare occurrence of flat vaults in excavations does not imply their restricted use. In reed architecture we find them widely used ever since the remotest times.Archaic drawings have preserved for us the aspect of such diverse constructions as boatcabins, huts, sanctuaries, carrying chairs, covered with flat vaults, and arches of bent and pliable materials such as reeds, palms, or papyrus stalks. We know of such vaults in the hieroglyphs showing facades of pavilions, coloured red. One is justified in speculating whether the upper portion of the hieroglyph represents the structure of curved stems in the facade or is an attempt to indicate the ribs along the vault, with vanishing decrease of size due to perspectival deformation. Such ribs are represented on the outer face of an archaic boat model. The facade of a Hathor temple, similar to those of the North and South buildings of the Djoser pyramid complex, is shown in detail at Deir el-Bahari.
Archaic flat arches in brick are known. Among the earliest examples are the brick arches of the IIId Dynasty at Beit Khallaf, in the Djoser complex at Saqqara, in the Tomb of Idu (VIth Dynasty) at Dendara, in a passage of Ra’hotep’s tomb, and in Kanofer’s chapel  at Giza. Superstructures of tombs imitate such vaults on their exterior, and show coloured ribs transversal to the tunnel. Later pictured data add to this list, by showing us the use of wooden doors, mobile tanks, sarcophagi and, transposed in brick or stone, doorways, silos, magazines and superstructures of tombs represented with flat arches or vaults as coverings. Chapels and kiosks of the New Kingdom and later periods seem to have been covered with flat vaults of wood.
Flat arches and vaults were actually imitated in stone in the funeral chamber of the Sesostris II Pyramid at Illahun, in a Middle Kingdom mastaba at Dahshur, in a subterranean passage cut in the rock and propped up with sandstone arches in two halves at Deir el-Bahari and in the chapels of Seti I Temple at Abydos. Rock-cut tombs and temples exhibit the same features at Beni-Hassan (Amenemhat, Khnumhotep), Aswan (Sarenput), in the sanctuary of the Ra’mses II Temple at Wadi es-Sebu’a (XlXth Dynasty) and in the vaults of the Serapeum. It is quite significant that both vaults in the Khnumhotep II and Amenemhat
rock-tombs at Beni-Hassan are decorated with an imitation of matwork hung from the head purlin.
Besides, various Middle Kingdom, models of brick houses show flat vaults and arches used in roofs and mulqafe. One of these has even ribs similar to those described.
Flat brick vaults were used in Hellenistic times as is shown by beautifully preserved examples in the chapels at Hermopolis-West and Karanis. The courses are inclined and the thickness
is of two bricks, the lower placed as stretcher in the direction transversal to the axis of the
vault, carrying a course of headers.
Coptic architecture and even modern local building craft exhibit a free use of the flat vault.
One may surmise that flat arches and vaults were as extensively used as barrel or catenary-curve ones, but being rather weaker they have survived only sporadically.
Vaults of the catenary or «sacred» curve occurred also in the excavations, not as beautifully intact as the flat vault of Nfri, but having interesting features, one being of the ribbed type, another with a reinforcing arch.
A long room was found covered with a partly preserved tunnel vault with ribs, similar to those of the archway of Nfri in size, colour, and the feature of flat string at the springing of the curve. Structurally, however, the vault is quite different, the bricks being placed as stretchers with their long side transversal to the axis of the tonnel.
This requires a different shape of the bricks. In fact, every semi-circular thickness of rib is formed of two adjacent bricks having their smallest side moulded into a quarter of a cylinder.
The courses are inclined, the initial one leaning against the back wall of the tunnel, a method used to avoid centring in the ordinary simple catenary-curve vault. Such a disposition is known from other examples in the Minor Cemetery (G2098, G3033). In Sab.fs tomb a barrel vault had such bricks
interlocking. In another mastaba the rib is moulded in one of the medium sides of the brick, shaped into a semi-circle.
All these sporadic ways of representing the same inner aspect of a ribbed vault point to the important fact that the architect knew no settled structural rule for the execution, but used his own creative ability. The aspect of the reeded roof was important, the method of obtaining it subsidiary.
The excavations in the Mastaba of Nfr-ihii adjoining that of Nfri have brought to light the remains of a catenary-curved vault in the vestibule of the chapel. It displays the feature of a reinforcing arch in the middle of its length, springing flush from the wall, at about the same height as the vault itself, but being very likely of a lower curve, probably round or even flat. This arch shows a moulding semi-circular in section, beginning a little above the springing, from a rounded end. The aspect would have reproduced that of a curved reed projecting from the inner face of the arch. Here again only a direct transposition from a reed prototype could have led to this unique feature.
It is worth pointing out that the catenary-curve arch or vault is much less frequent in surviving buildings than the semi-circular or barrel ones, both in the representations and in the imitations in stone or rock-hewn constructions. Are we entitled by this to assure that the same infrequency applied to the total number of arches and vaults that were built ? The flat curve could surely cover larger spans with a much more economical head. Thus we find a Middle Kingdom model representing a flat vault in the ground floor and a catenary-curve one on the first floor. Being more stable on account of less inner tension stresses, this type has survived more easily in existing examples in the Giza Necropolis (Tombs of Ahtj-htpw); Seneb,. . . and elsewhere.
No intact brick dome was discovered this season, but only what appears very probably to be tbe springing of such a covering. This occurs over a small room (serdab ?), square in plan, in the shape of small roundings corbelling at the corners of the walls. More substantial remains are known in Seneb’s tomb at Giza, discovered some time ago by Professor H. Junker.
The method of construction is not clear : it seems that the courses of stretchers are somewhat tilted and grow in narrower circles as the height increases, forming corbelling courses.
The section of the dome appears to be a flat semi-circle.
Representations of reed domes are known from the earliest times. They are shown covering huts, sanctuaries or silos and are flat-shaped. Later these structures were copied in brickwork as is shown by scenes of silos and in the superstructures of tombs, as coverings of doorways or of pylon towers.
Models of Middle Kingdom houses illustrate the use of brickwork domes or cupolas.
Such elements appear also inside the superstructures of Middle Kingdom tombs and in the
Meroitic pyramids.
Small cupolas were found over small chambers or kirns. Tombs at Abydos and Deir el-Bahari made use in the interior rooms of their superstructures of domes of ogival section built of horizontal rings corbelling one above the other.
The remains of the covering over the small quadrangular room in Nfri’s mastaba, together with the well-preserved dome of Seneb, appear to be the only surviving Old Kingdom attempts to cover a square plan with a cupola, using (pendentives ?). A tomb of the New Kingdom offers an example of similar elements. This brief survey of the occurrence of brick vaults and domes since the earliest times in
reed architecture and their transposition into brickwork, later copied in stonework, shows
the precedence of this kind of covering over others using wooden logs or beams.
The flat-curved arch and vault represented in archaic drawings is now known to have survived in Old Kingdom architecture on a scale hitherto unsuspected. The curve occurred in nature: it is the one shown by a papyrus stalk bending under the combined weight of a bird’s nest and a predatory ichneumon, by bundles of reeds carried by dwellers in the marshes or imitated in papyrus boats.
The method of tracing the curve as stylized by architects seems to have been very close to that for a three-centred arch. In the arch or vault of Nfri, some kind of centring must have been used, both internal and external faces being open and the span being rathe extensive.
That the architects of the Old Kingdom should have attached such importance to the reproductions of features unrelated to brickwork and by no means only decorative, shows that those had been outstanding in the original architecture. These ribs are clearly transposed from bundles of reeds or pliable stalks. Pompeian red must have reproduced the colour of such materials when dry. Similar «ribs » were known in flat stone ceilings of the earliest period, as in the tombs of Hemaka, Hor-Aha, the Djoser pyramid complex at Saqqara and a tomb at Helwan-North. They are coloured the same red as the curved ribs of the Giza vaults. There is accordingly no ground for surmising a wooden origin for the so-called imitations of «logs» or «beams» in stone ceilings. There is much more likelihood that they too are imitations of bundles of reeds, used in horizontal coverings, either in flat ceilings or in the irregular vault peculiar to Egyptian architecture, evolved out of the animal-shaped hut of archaic times. Such a light ceiling of bundles of reeds would have been quite adequate to a light structure of reeds and mats, which formed the usual type of early archaic architecture.
The Pompeian red colouring, which has been considered as denoting a wooden origin for the «fluted» columns of the Djoser pyramid complex, is now known for certain to be a rendering of the colour of dried pliable stalks.
The theory that these columns imitated a wooden prototype, either directly or through an intermediate wooden stage, is deprived of its strongest support. Such a n intermediate stage is henceforth not to be taken into account. The colouring of the fluted columns of Djoser can be understood as reproducing that of the prototype : black for a lower plinth of mud daub, white for a string fillet of binding, either cord or leather, and the upper red for the natural hue of dried stalks.
Wooden architecture seems rather to be receding into the background. So is the theory of a sedentary architecture of mud and brick in Lower Egypt and Upper Egypt (?) a nomad architecture using light wood and wattle-and-daub materials. Such a view would suppose an abnormal evolution of architecture in this country, regardless of the natural influences of soil and climate, both vital in the history of any architecture. Upper Egypt must have dried up long before Lower Egypt, which was still in historical times covered with marshes. One would have more readily understood an inverse development, of sedentary
architecture, featured by stable structures of brick on the dry soil of Upper Egypt, and nomad or light buildings made of stalks of plants growing freely in the Delta marshes. Such was at any rate the case in the earliest period at Ur.
According to the documentary evidence reviewed, vaults and domes were copied directly from structures in light materials : pictures show types of flat and catenary-curve vaults, and domes on circular or square plans, while the ever growing corpus of archaic and Old Kingdom remains give reproductions of these featuring elements of vaults such as reed ribs, which have lost their original structural value and are rather difficult to transpose into brick or stone.
The miracle that was Egyptian architecture seems to have had only restricted recourse to wood and its style as well as its elements were mostly directly inspired from the early use of light plant materials.