The key to the history of medicine in the Middle Ages, then, is always the presence of Greek influence. This persisted in the Near East, and consequently serious scientific medicine continued to flourish there, at first among the Christians and later among the Arabs. It was not for any special incentive of their own that the Arabs became the intellectual leaders of Europe during the tenth and eleventh centuries, but the fact that their geographical position in Asia Minor close to Greek sources provided them with the opportunity to know the old Greek authors, especially in philosophy and medicine, and therefore to be almost forced to become the channels through which Greek influences were carried into the West once more. Before the coming of the Arabs, however--that is, before the rise of Mohammedanism--there was an important chapter of medieval medicine which is often not appreciated at its true worth. The contributors to it deserve to be well known, and fortunately for us in the modern time were properly appreciated during the early days of the art of printing, in the Renaissance time, and accordingly their books were printed, and came to be distributed in many copies, which have rendered them readily available in the modern time. In Asia Minor, where Greek influence persisted as it did not in Italy, we have a series of distinguished contributors to medicine, or rather, medical literature--that is, men whose books represent a valuable compilation and digestion of the important medical writings from before their time, often enriched by their own experience. The first of these was Aëtios Amidenus--that is, Aëtios of Amida--born in the town of that name in Mesopotamia on the Upper Tigris (now Diarbekir), who flourished in the sixth century. Aëtios, or in the Latin form Aëtius, wrote a textbook that has often been republished in the modern time, and that shows very clearly how well the physicians of this period faced their medical and surgical problems, how thoroughly equipped they were by faithful study of the old Greek writers, and how successfully they coped with the difficulties of the cases presented to them. He is eminently conservative, a careful observer, who uses all the means at his command and who well deserves the interest that has been manifested in him at many periods during the almost millennium and a half elapsed since his death.