MANY histories of philosophy exist, and it has not been my purpose merely to add one to their number. My purpose is to exhibit philosophy as an integral part of social and political life: not as the isolated speculations of remarkable individuals, but as both an effect and a cause of the character of the various communities in which different systems flourished. This purpose demands more account of general history than is usually given by historians of philosophy. I have found this particularly necessary as regards periods with which the general reader cannot be assumed to be familiar. The great age of the scholastic philosophy was an outcome of the reforms of the eleventh century, and these, in turn, were a reaction against previous corruption. Without some knowledge of the centuries between the fall of Rome and the rise of the medieval Papacy, the intellectual atmosphere of the twelfth and thirteenth centuries can hardly be understood. In dealing with this period, as with others, I have aimed at giving only so much general history as I thought necessary for the sympathetic comprehension of philosophers in relation to the times that formed them and the times that they helped to form.