PETRA ()) TUTpa, in ecclesiastical writers also ca, MTpat), the capital city of the NABATJEANS (q.v.), and the great centre of their caravan trade, is described by Strabo (xvi. p. 779) as lying in a level place, well supplied with water for horticulture and other uses, but encircled bya girdleof rocks, abrupt towards the outer side. The surrounding country was barren, especially towards Julea ; the distance from Jericho was three to four days' journey, and from Plicenicum on the Red Sea coast five (see plate VI., vol. vii.). According to Pliny (N. H., vi. 144) the little valley of Petra is not quite 2 miles across, and lies at the junction of two roads, from Palmyra and Gaza respectively, 600 miles from the latter. These and other ancient notices leave no doubt as to the identity of the site with the modern Wady MUsa, in the mountains which form the eastern wall of the great valley betvveen the Dead Sea and the Gulf of Akaba. Wady MUM, lies just north of the watershed between the two seas, in 30° 19' N. lat. and 35° 31' E. long.I Travellers coming up the Arabali usually approach the ruins of Petra from the south -west by a rough path, partly of artificial construc-tion 2 ; but the natural entrance is from the east down a narrow defile inore than a mile long, called the Sik (" shaft "). The Sik is a contraction in the valley of a stream which comes down from the east, rising in a spring now known as the Fountain of Moses (Ain MUsa),3 and passing between the villages of Eljf and `Aireh (Palmer). Both these places are ancient ; the latter is the fortress Wo`aira of YakAt,4 while Eljf, mentioned by Edrisi, is the " Gaia urbs juxta civitatem Petram " of the Onomasticon.5 -Below these and above the ravine the characteristic rock-cut tombs and dwellings of the Nabatamns begin to appear. But to reach the city proper from these upper settlements one must traverse the whole length of the defile, which is simply a narrow waterway, in some places not more than 10 or 12 feet broad, and walled in by rich brown or red precipices rising from 60 to 120 feet (De Luynes ; Stanley doubles this height) above the stream. In ancient times there was a paved path beside the channel, and remains of an arch spanning it are seen high in the air near the en-trance. Towards the lower end of the gorge, a turn in the dark path and the descent of a side valley admit a sudden flood of light, and here stands the most famous ruin of Petra, the so-called Khazna, or " treasury of Pharaoh," with a, rich facade of late P,oman style, not built but liewn out of the rose-coloured limestone. The next turn gives room for a rock-cut theatre, and from this point the gorge begins to open out into the little plain described by Strabo, and gives perhaps the most striking view of the multi-plicity of grottoes with elaborate classical facades which line the enclosing mountain-wall. The plain itself is strewn with ruins of temples and other buildings, and stairs once led up the rocky walls to higher structures, of which the most notable is now called the " convent " (Al-Deir). The grottoes are inhabited in cold weather by the Liya-thina Fellalyin, who also hold the upper part of the valley, and are so troublesome a,nd extortionate that no thorough exploration of the district has yet been carried out. It is not even known where the torrent-bed leads on leaving the plain of Petra. De Luynes describes the water as wholly alysorbed by the sands near the theatre, but there is an unexplored gorge to the south-west which is the con-tinuation of the valley.

The Nabatans, as we see from Diodorus, used Petra as a place of refuge and a safe storehouse for their treasures of frankincense, myrrh, and silver before they gave up their nomadic habits. But Petra was not only safe and well watered, it lay close to the most important lines of trade. The modern pilgrim-road from Damascus to Mecca, which has taken the place of the old incense-route, passes indeed a little to the cast by Ma'an. But to touch Petra involves no great detour even on this line, and in ancient times, when Gaza was the great terminus of the Arabian tra-de, Petra was the place where the Gaza road branched off from that to 13ostra, Palmyra, and north Syria. The route from Egypt to Damascus is also commanded by Petra, and from it too there went a great route direct through the desert to the head of the Persian Gulf. Thus Petra became a centre for all the main lines of overland trade between the East and the West, and it was not till the fall of the Nabatean kingdom that PALMYRA (1.r.) superseded it as the chief emporium of north Arabia. Many Roman and other foreign merchants were settled here even in the time of Strabo, and he describes the caravans which passed between it and Leuce Come on the Red Sea coast as comparable to armies.

Petral is a Greek name which cannot have been that used by the Semitic inhabitants, and from Josephus (Ant., iv. 7. 1 ; 4, 7) and the Onoinastica (ed. Lag., p. 286 sq.) it may be concluded that the natives called the place Rekem (cp-1), a designation probably derived froln the variegated colours of the rocks about Wady Mnsa, to which all travellers refer with admiration.2 But Petra had yet another ancient name familiar from the Bible. The Biblical Sela (generally- with the article 3fmri), a city of Edom (2 Kings xiv. ; Isa. xvi. 1 ; also Judges i. 36, where RV. has " the rock " ; perhaps also Isa. xlii. 11), appears to be identified with Petra by the LXX., and certainly is so by the Onomas6ca. Petra., in fact, or the "rock," seems to be simply a translation of Sela, but a somewhat loose one, - for the Hebrew name, corresponding to the Arabic Sal`, is properly a, hollow between rocks, just such a place as Petra is. The fortress of Edoin, according to Obadiah 3, lay "in the clefts of the Sela," and seemed impregnable. And that the name of Sela survived the Nabatacan occupation is known from Yalpit, who places a fortress Sal` in Wady Miisa (comp. Noldeke in Z.D.M.G., xxv. 259). Petra, therefore, was a city before theNabatwans, and, occupying one of the few cultivable spots in the dis-trict, probably never wholly ceased to be inhabited. This identification disposes of another which was accepted alike by the Jewish and Christian Aramaic versions of the Old Testament, and, passing from the Aranmans to the Arabs, has given rise to the modern names Fountain and Wady of Moses (comp. YaVit, iv. 879). According to these versions nem, Ilkam, or more precisely lIkern of (that is, Elji), is Kadesh Roma, where flowed the waters of Strife or " well of judgment" (Gen. xiv. 7 ; Num. xx. 1 sq., xxvii. 14), where Moses struck the rock. This view is ably supported by Greene (The Ilebrew Migration from Egypt); others identify Kadesh with 'Ain Kadis (Kudais) on the south border of Judxa.

Petra survived the fall of the NabatTan kingdom, and indeed most of the buildings may be dated from the 2d and 3d centuries. It appears froni coins that Hadrian took it into favour and gave it his name. But Palmyra absorbed its trade with the Persian Gulf, and long before Islam the great incense-route was deserted and left Petra, like the mote southern Nabat.pan city of Egra (Hijr), to fall into ruin. The ruins were an object of curiosity in the Middle Ages, and were visited by Sultan Bibars (Quatremere, /.e.). The first European to describe them was Burekhardt, and since his thne they have often been visited. See the descriptions, plans, and views of Laborde and Linant, Arabie Pelree (Paris, 1830-34) ; the Duc de Luynes, Voyage d'exploration a la mer mole, &c., Paris, s.a. ; Palmer, Desert of the Exodus, vol. ii., 1871 ; Stanley, Sinai and Palestine ; Guerin, Terre Sainte, 1883. (W. It. S.)