Only one archeological expedition has ever been sent into Mada'in Salih. That was in 1907 when two French priests from the School of Oriental Studies in Jerusalem made an exhaustive study which was published as Mission Archéologique en Arabie, by the Société des Fouilles Archéologiques in Paris. These excerpts sre taken from that study.
"In the spring of the year 1907 we left for Teima, Mada'in Salih and el-'Ela (Al 'Ula). Because of insurmountable difficulties only the second of those places could be visited and studied at leisure ... This volume, therefore, ... concentrates on Mada'in Salih, the ancient Hegra of the Nabateans, al-Hijr of Arab historians and geographers ..."
"The funerary monuments of Mada'in Salih, like most of those at Petra, are a form of architecture entirely unique which one finds only in the land of the Nabateans. From this point of view, therefore, we can talk about the Nabatean style ... But if one stops to consider the style a bit closer, it quickly becomes apparent that ... its originality consists of having grouped elements sometimes strongly dissimilar and of very diverse origin."
"A quick look at the tombs ... suffices at once to divide them into two main categories: those we might call 'battlement tombs' and... 'staircase tombs.' Both are distinguished by the upper part of the monument which one notices immediately. The former, much less numerous and also, in general, much simpler and smaller, are crowned by a convex molding supporting a row (sometimes two) of battlements of a special shape, sculptured in the rock ... The latter end up in a groove, generally called the Egyptian groove, surmounted by a double stairway of five steps each, parting in the center and rising toward the sides where the last steps form the two extreme corners of the facade ...
"The battlements, with the four or five steps that crown a large number of tombs, have often been considered to be of Assyrian origin. The Arabs, in their turn, must have passed them on to the Nabateans. Does one have to attach any sort of symbolism to the steps (of the battlements) ? We do not believe that the Nabateans did, any more than the Arabs did ... The Nabatean architects and their successors saw in the battlements a simple ornamental motif and they made them with four or five steps according to the height necessary for proportions agreeable to the eye.
"The second way of crowning the funerary tombs ... the 'double staircase' ... can well have been developed from the 'battlements'; it corresponds in fact to the two half-battlements placed at the extreme corners. The 'staircase' ornamentation is simpler than the other, maybe also less elegant, but has the advantage of lending itself to a more considerable development ... the number of 'steps' (of the 'staircases'), five, seems to have been adhered to rigidly. We only turned up one exception, a small tomb with four steps, and have not seen a single example of a crowning staircase with six steps."
"Among the different objects and symbols present on the facades of the tombs at Mada'in Salih we noted at once the vases placed at the angles, sometimes even at the top, of the pediment. There are two sorts. On the large monuments there are, ordinarily, large, fluted urns ... On less important tombs, the urns are replaced by small amphorae of elongated shape ..."
"The grotesque masks, sculptured in relief in the center of various niches and on the facade (of one of the tombs) have, in general, a character of their own. One could believe, at first sight, that they are mere capricious displays, but then, do not the two snakes that appear always with them give those masks a symbolic value? The head of the reptiles disappears invariably behind the human head near the ears, sometimes a little higher (and) images of snakes also appear on some of the monuments at Petra."
"Another theme of decoration on the large facades of al-Hijr is the eagle, posed at the top of the pediment crowning the door's frame...
"According to Doughty, the Arabs saw in those figures aquatic birds, whereas the Syrians took them for falcons or eagles. Their shape, however, is so characteristic that one can say without hesitation: they surely are eagles."
"On another tomb, two animals above the door also deserve special mention. Their bodies look very much like those of a lion or, rather, a lionness. Could the six-petalled star placed between the two animals be the symbol of Venus, typified usually by a star with six or eight petals?"
"The sphinxes seen above the doors (of two tombs) are also, very likely, the fantastic beings which, like the lions, are carved on a large number of monuments for the purpose of decoration, but also with an allegoric purpose. The two decorating (a certain tomb) have a beardless human face and the body of an animal difficult to identify. Seeing it, one thinks not so much of a direct and somewhat unsophisticated copy of a model of Egyptian origin, but rather of the influence of a Phoenician theme which was already obsolete at the time it impressed the Nabatean traders."
"The inscriptions on the tombs of Mada'in Salih date from the year 1 B.C. till A.D. 75. It is possible to believe that some monuments preceded or came after these dates but it is difficult to deviate very much. We believe also that one would not be far from the truth in estimating that the period during which the facades of all the tombs were executed, was, more or less, one century. Most of the tombs, and the finest ones, date back to the reign of Aretas IV (9 B.C. until A.D. 40) ..."
"Inscriptions and graffiti on the tombs and also on the rocks at Mada'in Salih are in Nabatean (the most numerous and interesting), Minean, Lihyanite, Thamudic, Greek, Arabic and Turkish."
"Most Nabatean texts tell at length by and for whom a tomb was cut ('by Husabu son of Nafiyu son of Alkuf, of Teima, for himself and his children and Habu, his mother and Rufu and Aftiyu his sisters and their children'); they may include a warning, and sometimes a curse, to all who make inscriptions in the tomb, or sell it, rent it or use it for whatever purpose. It is mentioned when the tomb was made ('in the month of Sebat in the thirteenth year of the reign of King Haretat of the Nabateans who loves his people') and, often, the names of the sculptors."
"Examining the tombs of Mada'in Salih well, one gets still another impression. The regard of the Nabateans for their dead has often, and without doubt justly so, been stressed. Yet their concept of the afterlife ... is not the only motif behind the creation of the splendid monuments one can admire at Petra and al-Hijr. There is so much frontage that pride must have had something to do with it. At al-Hijr, especially, the interior has been neglected compared to the exterior and it is clear that one wanted to do things grandly and beautifully to display his wealth and magnificence.
"The contrast is striking when after having seen the fine walls of Kasr el-Bint, one visits the necropoles of Thebes. There all the decorations are on the inside. The Egyptians, uniquely preoccupied with ideas on future life, carved out palaces in the bowels of the earth, the access to which had to be concealed with the utmost of care. With the greatest finesse they sculptured and painted reliefs never intended to be seen by the human eye. In contrast, the rich Nabatean merchant, often a parvenu, tried to beautify the outside of his tomb, and to give it an outward appearance of splendor. He reserved for the facade the finest workmanship the artists of the city were able to produce, while the burial chamber was more or less neglected.
"But one must not exaggerate or even generalize too much, though, because the Nabatean tombs of Petra, in their entity, are delicately executed, inside as well as outside, and the vaults have been hollowed out, and often hidden, with great care. This makes the slovenliness found in most of those at Mada'in Salih all the more evident. One might ask if the niches in the walls, made in haste and in great disorder, were not, to a large extent, the work of a later people, the Thamud for example. Some have been hollowed out so clumsily that the facades have been ripped open; it is difficult to believe that this would have been the work of the first owner, who had taken the trouble to carve himself such a fine monument. This way of interment is, it is true, also found in Petra, but it extremely rare, especially with the interior of the handsome tombs, while, in al-Hijr, it abounds."