The picturesque construction is a typical example of a castle-enclosure with a separate central tower surrounded by a wall and several smaller towers. Its origin is not certain. Some scholars attribute it to the Romans, who probably built a lookout tower at Vezio to control the shores of the lake on which, in the meantime, Varenna was built. Little is known about Vezio and the castle during the Dark Ages but the building definitely existed in the late Middle Ages. Some think the castle was originally built by the inhabitants of Comacina Island when they were exiled to Varenna after being defeated by Como in 1169. However, most scholars have rejected this theory; it is more likely that the islanders carried out substantial building work in Varenna as well as on the castle (which was surrounded by walls). The building assumed its present appearance and served as a watchtower and beacon, but also provided a safe refuge for the inhabitants of Varenna when it was repeatedly attacked by Como throughout the late Middle Ages. It was subsequently acquired by the parish of Varenna, then by the Sfrondati Counts and later by the Serbelloni family, who maintained it until the 19th century when it was taken over by the current owners (the Greppi Di Robilant family). Since 1994 the castle has been let to and run by the Associazione Turistica Castello di Vezio (Vezio Castle Tourist Association). It houses a permanent exhibition dedicated to the Lariosaurus, a medium-sized reptile that inhabited this region during the Middle Triassic (fossils have been found at Parledo). It is also a centre for training and caring for birds of prey, and holds falconry exhibitions.