important bridgehead toward the East, the city of Otranto was provided since the antiquity of defense systems and fortified works. The siege suffered by the city in 1067 seriously damaged the fortress that was repaired and reinforced a few years later at the behest of Roberto il Guiscardo. The reconstruction promoted in 1228 by Frederick II of Swabia instead remain evident traces of the tower of the median body cylindrical, incorporated in the bastion at the tip of the lance, and in curtain walls of the north-east. An analysis of the undergrounds suggests that the castle was set to a plant with a central core with quadrangular, scanned at the corners by cylindrical towers.
After the sack of Otranto In 1480, the year in which the whole South of Italy was the object of the Turkish attack, the castle had to be rebuilt, which he did Alfonso of Aragon, Duke of Calabria. At the end of the century, when the city was given as a pledge to the Venetians, the structure was further enhanced with the addition of artillery and mortars. The Aragonese phase there remain only a tower and part of the walls. The current appearance of the small fortress it owes to the Spanish viceroy, who made it a true masterpiece of military architecture. The two polygonal bastions added in 1578 on the side facing the sea, inglobarono the preexisting aragonese bastion.
Today the castle of Otranto has a pentagonal plan, surrounded by a large moat and punctuated by four towers, three circular in carparo and one with the tip directed toward the sea. On the fifth side, discovered, opens the drawbridge. The fortress otrantina inspired the first gothic novel of history, the castle of Otranto, written by Horace Walpole in 1764.