The document discusses the role of religion in medieval medicine. It explains that the powerful Christian Church influenced all aspects of medieval life, including people's beliefs about illness and health. It describes how the sick could be treated by doctors for the rich, apothecaries, monks with knowledge of ancient texts, or local healers. Diagnosis drew on ideas from astrology, astronomy, urine analysis, and the ancient Greek theory of the four humours. Ancient Greek medicine, especially the works of Hippocrates and Galen, formed the basis of medical knowledge even after being lost for a time from Western Europe.