Final answer:
The Third Lateran Council directed that clergy below the rank of bishop with leprosy be removed from office, while bishops could remain with an assistant. Leprous priests could celebrate Mass privately but not in public to avoid scandal. This reflects medieval attitudes towards leprosy and the maintenance of ecclesiastical hierarchy.
Step-by-step explanation:
The Third Lateran Council established guidelines on how the church should handle cases of leprosy among the clergy. It dictated that clerics below the rank of bishop who were afflicted with leprosy should be removed from office.
However, a bishop diagnosed with leprosy was not to be removed, but rather assigned an assistant who could take over some duties and receive a part of the bishop's income. This provision was made because removing a bishop was a difficult process and required legitimate due process. It was believed that destabilizing the hierarchy could harm the entire structure of the Church.
Moreover, the council indicated that a leprous priest should not celebrate Mass publicly to avoid scandal but could do so privately. This measure was taken to prevent the spread of leprosy, which, while not highly contagious, was stigmatized and required ethical considerations in treatment and isolation practices. This approach to leprosy among the clergy reflects the period's medical knowledge and social attitudes towards the disease.