So far, no method has been found to determine when the history of Petra began. Evidence suggests that the city was founded relatively late, though a sanctuary may have existed there since very ancient times. This part of the country was traditionally assigned to the Horites, probably cave-dwellers, the predecessors of the Edomites. The habits of the original natives may have influenced the Nabataean custom of burying the dead and offering worship in half-excavated caves. However, the fact that Petra is mentioned by name in the Old Testament cannot be verified. Although Petra is usually identified with Sela which also means a rock, the Biblical references are not clear. 2 Kings xiv. 7 seems to be more specific. In the parallel passage, however, Sela is understood to mean simply “the rock” (2 Chr. xxv. 12, see LXX). As a result, many authorities doubt whether any town named Sela is mentioned in the Old Testament.
It is unclear exactly what Semitic inhabitants called their city. Apparently on the authority of Josephus (Antiquities of the Jews iv. 7, 1~ 4, 7), Eusebius and Jerome (Onom. sacr. 286, 71. 145, 9; 228, 55. 287, 94), assert that Rekem was the native name and Rekem appears in the Dead Sea scrolls as a prominent Edom site most closely describing Petra. But in the Aramaic versions Rekem is the name of Kadesh, implying that Josephus may have confused the two places. Sometimes the Aramaic versions give the form Rekem-Geya which recalls the name of the village El-ji, southeast of Petra. The capital, however, would hardly be defined by the name of a neighboring village. The Semitic name of the city, if not Sela, remains unknown. The passage in Diodorus Siculus (xix. 94–97) which describes the expeditions which Antigonus sent against the Nabataeans in 312 BC is understood to throw some light upon the history of Petra, but the “petra” referred to as a natural fortress and place of refuge cannot be a proper name and the description implies that the town was not yet in existence. Brünnow thinks that “the rock” in question was the sacred mountain en-Nejr (above). But Buhl suggests a conspicuous height about 16 miles north of Petra, Shobak, the Mont-royal of the Crusaders, aka Montreal.
More satisfactory evidence of the date of the earliest Nabataean settlement may be obtained from an examination of the tombs. Two types may be distinguished—the Nabataean and the Greco-Roman. The Nabataean type starts from the simple pylon-tomb with a door set in a tower crowned by a parapet ornament, in imitation of the front of a dwelling-house. Then, after passing through various stages, the full Nabataean type is reached, retaining all the native features and at the same time exhibiting characteristics which are partly Egyptian and partly Greek. Of this type there exist close parallels in the tomb-towers at el-Iejr in north Arabia, which bear long Nabataean inscriptions and supply a date for the corresponding monuments at Petra. Then comes a series of tombfronts which terminate in a semicircular arch, a feature derived from north Syria. Finally come the elaborate façades copied from the front of a Roman temple; however, all traces of native style have vanished. The exact dates of the stages in this development cannot be fixed. Strangely, few inscriptions of any length have been found at Petra, perhaps because they have perished with the stucco or cement which was used upon many of the buildings. The simple pylon-tombs which belong to the pre-Hellenic age serve as evidence for the earliest period. It is not known how far back in this stage the Nabataean settlement goes, but it does not go back farther than the 6th century BC.
A period follows in which the dominant civilization combines Greek, Egyptian and Syrian elements, clearly pointing to the age of the Ptolemies. Towards the close of the 2nd century BC, when the Ptolemaic and Seleucid kingdoms were equally depressed, the Nabataean kingdom came to the front. Under Aretas III Philhellene, (c.85–60 BC), the royal coins begin. The theatre was probably excavated at that time, and Petra must have assumed the aspect of a Hellenistic city. In the reign of Aretas IV Philopatris, (9 BC–AD 40), the fine tombs of the el-Iejr type may be dated, and perhaps also the great High-place.