Byzantine hospitals developed out of Christian institutions for the poor and homeless. Philanthropy provided the initial impulse to create hospices (xenons) and to expand these institutions into specialized medical centers (iatreons or nosokomeions). However the Byzantine nosocomeions resemble more closely modern hospitals than they do any of the institutions of Greek-Roman antiquity or any of the houses of charity in the Latin West during the Middle Ages. Since the 4th century the Byzantine hospitals have stressed the central position of the nosocomeion in Byzantine society at the intersection of state, ecclesiastical and professional interest. In the great cities and in the capital, more than hundred hospitals worked in the East-Roman Empire. The Byzantine hospital rules guaranted patients private beds, required physicians to wash their hands after each examination and arranged the physical plant to keep all the sick warm. The Byzantine hospitals had separate sections (in modern terms: surgery-trauma surgery, internal medicine, ophthalmology, etc.) and at the beginning of the sixth century a separate institution for women. From the sixth century at least, bathing facilities normally adjoined Byzantine nosocomeia. By the twelfth century Byzantine hospitals also set aside a room or perhaps a separate building to treat outpatients. In addition to the main dormitories the surgery, baths and outpatient clinic, the large parts of hospitals also had separate rooms (or adjoining buildings) for library, for lecture hall, for administrative functions and record keeping for storage and for other services.