Nineteen caliphs of the race of Omar succeeded Ali, and after these came the dynasty of the Abassydæ, descended by the male line from Mohammed. The second caliph of this race, named Almanzor, removed the seat of empire to Bagdad (762), and introduced learning and the culture of the sciences, which his successors continued to promote with zeal and liberality. This was some recompense for those indignities which had been cast upon literature by the brutal Omar. Perhaps the obligations of modern Europe to Arabia at this time have been overstated; but it is not to be denied that learning, almost totally excluded and extinct in Europe during the eight and ninth centuries, found an asylum here. It has been matter of dispute how the tastes of these fierce Arabians became thus first directed. They probably owed it to the Greeks; but it is certain that what they got they returned with interest. We are said to derive our present arithmetical figures from this strange people; and geometry, astronomy, and alchemy were their favorite pursuits. The graces of light literature were not neglected, as is shown by the One Thousand and One Nights’ Entertainments, a production of this period, which still continues to solace the hours of childhood and old age among ourselves, and attests the extent of fancy and the variety of genius among those that gave it birth. Haroun al Raschid, who flourished in the beginning of the ninth century, is celebrated as a second Augustus. He was cotemporary with Charlemagne, and communications of a friendly nature are said to have passed between them.