Structure 26 (ST 26 on fig. 2), built at the very edge of a promontory protruding towards the city centre (figs. 5–8) was also partially excavated this year. This is the structure that was already investigated by Morton in the early 1950s and, therefore, the same that had been interpreted by Bennett as being a Nabataean temple.
Fig. 5: Umm al-Biyara, detail of plan showing ST 26 (plan: G. Teltsch and W. Kennedy)
After verification it turned out that the rectangular structure previously recorded is only part of a more substantial building, continuing on at least three sides (N, S, W), while towards E the steep cliff made a further extension impossible. However, the regularly cut off rock that was previously interpreted as steps suggests instead the positioning of a major wall, using the classical Nabataean technique of a zigzag-like contact between the built and the rock-cut parts of walls. Within the main structure, i. e. the one already mapped by the British in 1965, parts of the original floor slabs still are visible in situ. In the SE part of that room, a rectangular structure built of two ashlars and measuring 66 x 80 cm stands directly on the floor slabs. This structure is likely to be the lowest layer of a rectangular pillar. Perfectly aligned to it but a few metres to the W stands an ashlar of a similar construction.
Fig. 6: Umm al-Biyara, overall view of ST 26 with Wadi Mousa in the background (photo: S. G. Schmid)
Within this structure several fragments of Nabataean horned pilaster capitals were found; another one of the same type and with the same dimensions (21 cm of height) was collected from the rubble of the same building sloping down the cliff on the S side in 2010. The pilaster capitals are likely to have decorated the back walls of the supposed courtyard. While excavating the N half of the visible structure, it turned out that the back wall actually shows a row of pedestals very similar – although smaller – to the pedestals of the temenos gate to the Qasr al-Bint area McKenzie 1990. (fig. 7). On top of these pedestals one has to imagine pilasters and indeed, several fragments of pilaster bases and the above mentioned capitals were found. This would indicate a respectable height of that room, reaching around five meters. Surprisingly, nothing was found in the N-half that could correspond to the above mentioned pillar base that is visible in the S-half. This would indicate a very wide colonnade and, therefore, the room must have been much bigger that the nowadays visible remains. Indeed, in the steep slope to the S, several traces of retaining and supporting walls are visible and would point to an impressive size of that construction.
Fig. 7: Umm al-Biyara, ST 26. Huge hall, backwall with pedestals, small door in between, big door to the right (photo: S. G. Schmid)
Access to this nicely paved room was possible trough a doorway at its NW corner (figs. 7. 8), measuring 1.25 meters in width. Whether this was the main entrance or not cannot be decided at this time, especially since an important part of the room to the S is missing due to its collapsing into the steep slope. However, another doorway gives access to this paved room: Between the two northernmost pedestals at its back wall a very narrow (50 cm) opening leads to a small staircase leading first in EW-direction and then turning to NS-direction (fig. 7). This is yet another indication that the original organisation of this space was far more complex than actually visible.
Fig. 8: Umm al-Biyara, ST 26. Huge hall, carelessly constructed side E-W-wall with big door to the left (photo: S. G. Schmid)
What is at first sight striking is the difference between the very accurately cut floor slabs reaching respectable dimensions up to 100 cm x 200 cm in size (figs. 6. 8) and the rather carelessly constructed walls (fig. 8). Again, a possible explanation probably lies in the materials used for the respective needs of construction. While the available rock at the top of Umm al-Biyara can easily be quarried into slabs, it is not very suitable for quarrying ashlars. Therefore, walls were mostly built of smaller stones and even rubble and then carefully covered by plaster, so that at the end there was no visible difference for the visitor. Only in exceptional cases, i. e. for statically important architectural members, substantial ashlars were used that most probably had to be carried up the hill from the city centre or even further away.
Fig. 9: Umm al-Biyara, ST 26. Different limestone and marble fragments from floor and wall decoration (photo: S. G. Schmid)
From the excavated parts of ST 26 come some hints regarding its ancient interior decoration. Several fragments of a yellowish limestone with small shell inclusions were found, belonging to very carefully cut slabs (fig. 9 bottom row). These slabs are of excellent quality and show a nice natural decoration pattern once they are wet, due to the shell inclusions. Beside rectangular examples, there are several fragments clearly showing a triangular shape and, therefore, being most likely from an opus sectile decoration combining different type of stones of different colours. This hypothesis is supported by several fragments of white marble slabs (fig. 9 top row) as well as marble slabs with greenish and bluish veins (fig. 9 central row).
Fig. 10: Umm al-Biyara, ST 26. Late Roman – early Byzantine lamp fragment in situ (photo: S. G. Schmid)
No definitive indication as for the construction date of ST 26 have been found so far, although construction technique as well as the types of architectural members would suggest a date somewhere within the second half of the 1st c. CE. More important are the indications as to the end of the use of the room. Beside the observation that the debris of the collapsed walls would rather indicate an destruction by earthquake, several fragments of late Roman – early Byzantine lamps were found, one of them directly on the floor slabs (fig. 10). It would seem, therefore, that the structure to which the nicely paved room belonged was in use until one of the devastating earthquakes that hit Petra, most likely the one of 363 CE.
