Since their establishment on the banks of the Tigris, the Abbasside caliphs had departed widely from the ancient traditions of their race; and the warlike ardour and stern simplicity, which had won so vast an empire for ‘Omar and his contemporaries, presently gave way to effeminate luxury and useless extravagance. But although this change was gradually undermining their power, and tending to the physical degeneracy of the race, it was not unproductive of good; and the immense riches and careless liberality of the caliphs attracted to the Court of Baghdád the learned men of the Eastern world. The Arabs were not an inventive, but they were eminently an acquisitive people, and, “Græcia capta ferum victorem cepit,” the nations conquered by their arms were made to yield up intellectual as well as material spoils. They had neither art, literature, nor science of themselves, and yet we are indebted to them for all three; for what others produced and neglected, they seized upon and made their own. Born in the black shapeless “tents of Shem,” and nursed amidst monotonous scenery, the Arabs could conceive no grander structure than the massive tetragonal Ka‘abah; but Persia was made to supply them with the graceful forms and harmonious colours suggested by the flower-gardens of Iran.[38] The art of painting, cultivated with so much success in Persia even at the present day, found but little favour with the iconoclast followers of Mohammed; but its influence is seen in the perfection to which mural decoration, writing, and illumination have been brought by the professors of Islam. Caligraphy has been cultivated in the East to an extent which can be scarcely conceived in this country; and the rules which govern that science are, though more precise, founded on æsthetic principles as correct as those of fine art-criticism here. Footnote 38: Nearly all the technical terms used in Arab architecture are Persian—an additional proof that the so-called Saracenic style is of foreign and not native origin. A people whose hereditary occupation was war and plunder, and who looked upon commerce as a degrading and slavish pursuit, were not likely to make much progress, even in simple arithmetic; yet, when it was no longer a mere question of dividing the spoils of a caravan, but of administering the revenues and regulating the frontiers of conquered countries, then the Saracens both appreciated and employed the exact mathematical sciences of India.