Avicenna, an Arabian physician and Mahometan doctor, reduced the science of medicine to a systematic form, including almost everything that had been written on the subject by his predecessors: he was versed in Greek literature, and is said to have committed Aristotle’s Metaphysics to memory. The first conquests of the Saracens in Asia, Africa, and Spain, during the seventh and eighth centuries, were almost fatal to the interests of learning. But no sooner had they well established their power in the conquered countries, than the Caliphs sought to rekindle the light of knowledge. During two or three centuries, Bagdat in the East, and Cordova in the West, were the seats, not only of splendid monarchies, but of science, general learning, and great refinement. It was, however, chiefly the mathematical and physical sciences that were cultivated by the Arabians. They possessed imperfect and corrupted translations of several of the Greek authors, especially of Aristotle, Theophrastus, Euclid, and Dioscorides; and they had some general, though imperfect, acquaintance with the Greek historians. Some of the Latin translations, made by the order of Charlemagne, were derived from these Arabian versions. Michael Psellus, a Greek physician, and a monk, wrote upon subjects of all kinds: “There was no science which he did not either illustrate by his comments, or abridge, or reduce to a better method.--A man celebrated for the extent of his acquirements in divine and human learning, as his many works, both printed and in manuscript, evince.” Lanfranc, by birth an Italian, was created archbishop of Canterbury by William of Normandy; he promoted learning among the clergy, and was himself reputed to be universally accomplished in the literature extant in that age. Anselm, the disciple and successor of Lanfranc, in the see of Canterbury, was also in repute for general learning. The works of Suidas, a Byzantine monk, like those of Photius, contain a vast store of various learning, singularly useful on points of criticism and literary history. The lexicon of this writer, besides the definition of words, contains accounts of ancient authors of all classes, and many quotations from works that have since perished. Sigebert, a monk of Brabant, has left a chronicle of events from A. D. 381 to his own times, 1112, and a work containing the lives of illustrious men. The name of Anna Comnena, daughter of the emperor Alexius Comnenus, and wife of Nicephorus Bryennius, distinguishes the early part of the twelfth century. She wrote an elegant and eloquent history of her father’s reign. This work displays not only a masculine understanding, but an extensive acquaintance with literature and the sciences.