Nor does the paradox confine itself to her terrain; her inhabitants and their social institutions, particularly during the seventh century, exhibited corresponding discrepancies. Although all Arabs were ruled by nearly identical codes of honor, morals and manners, spoke a generic tongue, and were passionately patriotic, they were yet divided into tribes that bowed before countless fetishes, conversed in individual dialects, and were ever ready to fight to the death for the supremacy of their particular clan. At times of national danger, it is true, they fervently abandoned all local prejudices in a tumultuous display of chauvinism; but such contingencies were rare and, since the vague, immemorial inception of her history, Arabian tribes, on the slightest pretext or on no pretext at all, had frequently plunged with limitless enthusiasm into the gratifying job of slitting fraternal throats. All these various tribes, moreover, were grouped into two fairly distinct divisions: the city-dwellers and the Bedouins. From her earliest days, Arabia had depended on caravan trade for her subsistence. In the times of Abraham, Moses and Solomon, her traders had carried the fragrant spices and other products of Palestine and Arabia--cassia, cinnamon, frankincense, myrrh, gums, leather and coffee--into Egypt; and, conversely, the “Kings of Arabia” had also freighted into Judea and their own beloved land the priceless rarities of the Orient: ivory, ebony and precious gems. For the dangers of ocean commerce made a land route absolutely essential for the exchange of merchandise between the East and the West, and Arabia alone supplied the necessary bridge for this extensive barter. Caravans from every nation, therefore, had for centuries passed each other on her sere surface; her oases had thus become cynosures where rest and refreshment could be had; and so by degrees these centres of repose became the sites where marts, temples and sanctuaries sprang indiscriminately up. These nuclei of elementary civilizations led, little by little, to the development of an urban population where those Arabs who chanced to be disposed toward peace and business could lead a moderately serene life. But the instinct of nomadism was incalculably strong in most of Arabia’s sons, and myriads of men, yielding to the powerful atavistic impulse, gladly relinquished the relatively soft environment of urbanism in order to undergo, with fatalistic indifference, the hazards of a roaming, marauding, desert life.