The thirteenth century is memorable by the appearance of three great men, Roger Bacon, Albertus Magnus and St. Thomas Aquinas. Albert was born in Suabia in 1193, the descendant of a celebrated and powerful family. He may be reckoned as the best product of the middle ages. He studied in Padua and Bologna, taught at Cologne and Paris (1245) and returned to Cologne. He became provincial of the Dominicans in Germany in 1254, and was Bishop of Ratisbon (in 1260) till he resigned about 1263. He was the friend of kings and popes. His great service to the church was a systematic presentation of the philosophy of Aristotle with a full accompaniment of Arab commentary. Among his contemporaries he was known as Doctor Universalis, and, in the history of the world, is especially famous for his works on physical science. Like all the learned men of his time he was supposed by the vulgar to practise magic and, as a matter of course, he sought the philosopher's stone. It was even currently believed that he paid the large debt of his bishopric of Ratisbon with transmuted gold. The flowers that he grew in the winter time, which the wondering townsfolk called magical, were in all likelihood the product of the first hot-house constructed in Europe. An edition of his works in twenty-one volumes was first published in 1651. This complete collection shows, in the first place, that he was thoroughly familiar with all the learning of the Arabs up to his own time. He was to the west what Avicenna was to the east, an encyclopedia of all knowledge. His philosophy is, of course, Aristotle's, elucidated by the schools of Arabia and Spain. His works on physical science are, in a large degree, mere reproductions of Greek treatises, but they are