The first development at Scicli was around the Castello dei tre cantoni at the top of San Matteo hill that overlooks the town. The Castello dei tre Cantoni is actually composed of two separate fortifications, the Castelluccio higher up and the Castellaccio at a lower level.
This was a defensive structure that, over the centuries, was enlarged and used first by the Arabs, then by the Normans and then later as a military outpost of the County of Modica. The current castle is dated to the 13th century although studies date its origins to the first half of the 12th century.
The Castle has a triangular tower, while to the north-east stands a large wall terminating in a quadrangular tower. The reason for having an unusual triangular tower is unknown, but thought to be symbolic (possibly related to the three points of Sicily itself) rather than a military function.
References:The Chapel of St. Martin is the only completely preserved Romanesque building in Vyšehrad and one of the oldest in Prague. In was built around 1100 in the eastern part of the fortified outer ward. Between 1100 and 1300, the Rotrunda was surrounded by a cemetery. The building survived the Hussite Wars and was used as the municipal prison of the Town of the Vyšehrad Hill.
During the Thirty Years’ War, it was used as gunpowder storage, from 1700 to 1750, it was renovated and reconsecrated. In 1784, the chapel was closed passed to the military management which kept using it as a warehouseand a cannon-amunition manufacturing facility. In 1841, it was meant to be demolished to give way to the construction of a new road through Vyšehrad. Eventually, only the original western entrance was walled up and replaced with a new one in the sountren side. The dilapidating Rotunda subsequently served as a shelter for the poor.