By the 12th century, the hospital was already operational, and its ruins are preserved in the garden behind the baptistery. From the 16th century onward, it was managed by the “Congregation of St. Catherine,” which cared for the sick, the poor, and pilgrims. Surviving historical documents tell us of an efficient organization of doctors and staff. Many who died here, as evidenced by numerous wills, were buried in the “Terrasanta,” the underground cemetery located behind the baptistery.

Adjacent to the baptistery stands the Chapel of St. Catherine, home to the namesake congregation, which houses a valuable panel painting depicting the Trinity.

Behind it, a large, well-maintained garden is enriched with numerous archaeological finds.