from Persia, Rome, and Greece being found on the site. More recent work in Oman and Yemen indicated that this fortress was the easternmost remains of a series of desert caravanserais that supported incense trade. As far as the legend of Ubar was concerned, there was no evidence that the city had perished in a sandstorm. Much of the fortress had collapsed into a sinkhole that hosted the well, perhaps undermined by the removal of ground water for irrigation. Rather than being a city, interpretation of the evidence suggested that "Ubar" was more likely to have been a region—the "Land of the Iobaritae" identified by Ptolemy. The decline of the region was probably due to a reduction in the frankincense trade caused by the Christianization of the Roman Empire, as Christianity did not require incense in the same quantities for its rituals. Also, it became difficult to find local labour to collect the resin. Climatic changes led to desiccation of the area, and sea transport became a more reliable way of transporting goods. The archaeological importance of the site was highlighted by satellite imagery that revealed a network of trails, some of which passed underneath sand dunes tall, which converged on Shisr. Image analysis showed no further evidence of major undocumented sites in this desert region, which might be considered as alternate locations for the Ubar of legend. Critical reception The Saudi Arabian press was generally sceptical about the discovery of Ubar in Oman, with Abdullah al Masri, Assistant Under-Secretary of Archaeological Affairs stating that similar sites had been found in Saudi Arabia over the past 15 years. In Ashawq al Awsat he explained: "The best of these sites was when, in 1975, we uncovered more than one city on the edge of the Empty Quarter, in particular the oasis on Jabreen. Also the name of Ubar is similar to that of Obar, an oasis in eastern Saudi Arabia. We must await further details but so far we have far more important discoveries at Jabreen or Najran." However, Professor Mohammed Bakalla of King Saud University wrote that he would not be surprised if Ad's nation cities were found underneath the Shisr excavation or in the close vicinity. More recent academic opinion is less than convinced about the accuracy of Clapp's findings. One reviewer noted that Clapp himself did not help matters by including a speculative chapter about the king of