The increased prevalence of _leprosy_ in Europe in the Middle Ages is often attributed to the Crusades.[12] Leprosy was very widespread in Germany, France, Italy, and other countries of Europe before the Crusades; according to Hirsch it appeared in the Roman Empire in the first century before the birth of Christ, but did not become very prevalent until later. Legal regulations governing the marrying of lepers date back as far as the seventh century, while the earliest reports regarding leper-houses come down from the eighth and ninth centuries. Most leper-houses, however, were built between the eleventh and thirteenth centuries, and although the reverse opinion has been expressed, it is nevertheless improbable that the building of these houses was not due to the increased prevalence of the disease. Inasmuch as leprosy was very widespread in the Orient, where numerous crusaders contracted it, as indicated by the fact that institutions were founded there for its victims, many crusaders doubtless returned with the disease in their systems. But regarding this matter we shall never have absolutely reliable information; for it is assumed that many people suffering from other chronic skin diseases were placed in the leper-houses. A careful study of the available data, however, leads us to believe that wrong diagnoses were not so frequent as to account for the large number of cases of leprosy in the eleventh, twelfth, and thirteenth centuries. Admittance to leper-houses was regulated by many precautionary measures, and the diagnosis of the disease was made by churchmen, even bishops, who without doubt necessarily acquired a good eye for the disease in the course of time. Not until later, when we may be certain that leprosy was no longer brought from the Orient, was the disease probably now and then confused with syphilis.