Monasterio de San Juan was founded in 1091, when the kings Alfonso VI and Constance of Burgundy donated a small land to monk Lesmes, who came from the Chaise-Dieu abbey. In 1537 a fire destroyed practically the whole monastery. The reconstruction lasted until the confiscation. During the first half of the 19th century, several confiscations destroyed the heritage of the monastery and the hospital of San Juan. The monks were expelled from the monastery. The buildings were used as a prison.
The eight towns in south-eastern Sicily, including Ragusa, were all rebuilt after 1693 on or beside towns existing at the time of the earthquake which took place in that year. They represent a considerable collective undertaking, successfully carried out at a high level of architectural and artistic achievement. Keeping within the late Baroque style of the day, they also depict distinctive innovations in town planning and urban building. Together with seven other cities in the Val di Noto, it is part of a UNESCO World Heritage Site.
In 1693 Ragusa was devastated by a huge earthquake, which killed some 5,000 inhabitants. Following this catastrophe the city was largely rebuilt, and many Baroque buildings from this time remain in the city. Most of the population moved to a new settlement in the former district of Patro, calling this new municipality 'Ragusa Superiore' (Upper Ragusa) and the ancient city 'Ragusa Inferiore' (Lower Ragusa). The two cities remained separated until 1926, when they were fused together to become a provincial capital in 1927.