On the other hand, the influence of neighboring countries upon Arabia has been attended, in its turn, with consequences of the greatest importance. It was peculiarly fortunate that her geographical situation rendered her maritime cities--and in a still greater degree her interior settlements--entrepôts for the distribution of the luxuries of the East and West. Of the latter, in ancient times, and indeed until superseded by the doubtful advantages of Mecca, Petra was the most remarkable. The latter was a veritable troglodytic city. Its dwellings, excavated in the solid rock, disclose by their vast extent that at one time they must have sheltered a population of at least a hundred and sixty thousand souls. Nor was Petra the only town of this kind in Northern Arabia. Many others almost rivalled it in size and opulence, in the splendid architecture of their temples, in the vast ramifications of their commercial interests, in the sybaritic luxury of their inhabitants. Under such conditions a high degree of civilization must necessarily have been reached, which, however, had disappeared with the decline of Phœnician influence at a period long before the dawn of the Christian era. From an epoch not improbably coeval with the establishment of the first Egyptian dynasty there had been an almost incessant passing and repassing of strangers, attracted by the profits of the Ethiopian and Indian trade, upon the highways, which in every direction traversed the Peninsula. This continual intercourse with foreigners, the curious information of distant lands which the latter imparted, the mysterious dogmas of unknown faiths which they professed, their extensive learning and polished manners, insensibly enlarged the sphere of observation and activity, developed the mental faculties, and softened the rudeness of the wild tribes of the Desert. Many of these traders were Phœnicians and Jews whom a common origin, indicated, among other traits, by a striking similarity of language, brought at once into familiar and intimate contact. with the Arabs. The commercial intercourse of Arabia with Egypt is known from inscriptions to have existed for thirty-five hundred years before Christ, and that with Phœnicia may, not improbably, have been of equal antiquity.