The castle of Toolse was built in 1471 by the Livonian Order as defence against pirates sailing in the Gulf of Finland. During the Livonian War it changed hands several times, was apparently destroyed and later rebuilt. In 1581 French mercenary Pontus de la Gardie captured the castle for Sweden from Russia which had held it since 1558. The castle was destroyed again during the Great Northern War, ever since which it has laid in its current state of ruin.
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.