The results of the second excavation season by the International Umm al-Biyara Project (IUBP) mostly confirmed the results and hypotheses from the 2010 survey season and the first excavation season of 2011. Structure 26 and Structure 20 are situated on one of the most prominent spots of the hill, offering a splendid view over the city centre of Petra, and they must also have been visible from all over Petra. Furthermore, they are at the most distant point of the entire plateau in relation to the steps giving access to it. Irrespective of whether there were other paths leading up Umm al-Biyara, the one followed by the modern steps, which are a restoration of the Nabataean steps, surely was the most „official“ access to the plateau during the Nabataean period. Therefore, the bathing installation is both very prominent and at the same time very private, since access to it was strongly reduced and controlled. Since the bathing installation made use not only of water, already a luxury item in this specific location, but also of wood or other fuel needed to heat the floor and wall heating systems described above, we are facing an almost provocative display of wealth and luxury. Despite the fact that heated rooms per se were not necessarily considered a specific luxury item by the time of their construction, the fact that they are situated on top of the highest elevation in the region makes them outstanding, since every single twig that was burned in their praefurnia needed to be carried up the hill.
That this has to be a building out of the ordinary is further suggested by the general geo-strategic situation of Umm al-Biyara as described above. It is irrelevant whether Umm al-Biyara is the „rock“ of the Nabataeans reported for the year 312/11 BC by Diodorus: by the late 1st century BC and the 1st century CE, Umm al-Biyara must have been sufficiently important that not everybody was allowed to build there. It is precisely this combination of strategic importance and ostentatious demonstration of wealth that places these Nabataean buildings in close relationship with some of Herod the Great’s hilltop palaces. In Masada, Herodeion, Kypros and Machaerus (Machairous), heated rooms, usually as part of Roman style thermae, are an outstanding characteristic On the hilltop palaces of Masada, Herodeion, Kypros and Machaerus, see Netzer 2001b; Japp 2000; Lichtenberger 1999; Roller 1998; Nielsen 1994, 181–208; especially on their bathing installations see Netzer 1999. . Beside the pools etc. of major bathing installations, individual bathtubs are common to most of the Hasmonean and Herodian structures cited Cf. Netzer 1999. ; however, no bathtubs for two or three persons such as the one mentioned above in ST 20 seem to be attested from Herodian buildings.
We can assume that these Herodian installations were not only known to the Nabataean upper class Cf. Schmid 2009. , but especially the palace at Machaerus, situated on the eastern shore of the Dead Sea, must have been in many ways a sort of provocation to the Nabataeans. It seems, therefore, perfectly appropriate to suggest that the building on top of Umm al-Biyara consisted of something like the Nabataean response to the Herodian hilltop palaces. Probably the best overall comparison is offered, for the time being, by the Herodian palaces at Masada Specifically on Masada see Netzer 1991. . The general situation is the same, i. e. the Herodian buildings are distributed all over the plateau of the massive rock elevation that is Masada, and, as on Umm al Biyara, there is no common orientation for all buildings, rather they form smaller groups according to their successive dates of construction. There, too, the most luxurious and at the same time the most private structures, the ones known as the North palace, are placed at the spot opposite the main access to the hill. As at Umm al-Biyara, these Herodian structures are playing with visibility, incorporating the splendid panoramic view into the architectural display, as is especially true for the three levels of the northern palace. Likewise, they feature lavishly decorated bathing installations.
Despite the fact that Masada offers the best overall comparisons to our structures from Umm al-Biyara, in details most of the other Herodian residences can also be compared. For instance, the deliberate playing with visibility and the view is very prominent within Herod’s third palace at Jericho Netzer 2001: 231–286. . The triclinium B70 Ibid. 239. and the courtyard B55 Ibid. 251–254. from Jericho can be compared to our ST 26 with its extreme position built literally over the cliff. Since the southern wall of courtyard B55 in Jericho fell into the Wadi Qelt and cannot be reconstructed securely, as is the case with the eastern wall of our ST 26, in both cases a direct opening to the natural view would be possible.
The very promising results of our excavation season of 2012 definitely demonstrate the value of scientific documentation and research related to the Nabataean buildings on top of Umm al-Biyara. It is planned to continue our efforts in spring 2013; for the time being, the exposed structures have been backfilled in order not to expose them to the sun and rain. For the next season of the IUBP, one goal would be the completion of the plan of the bathing installation ST 20 in order to be able to better compare it to similar balnea. Furthermore, it would be interesting to excavate one of the structures identified in the 2010 survey that is not built directly on the cliff, but slightly higher above the next terrace of Umm al-Biyara. What was the function of these structures? Do they show the same chronology as ST 20 and ST 26? These and related questions would define the work of a future season.