Continuing along the Monti Lattari chain, you will reach the Castle of San Nicola de Thoro-Plano, a historical fortress built in the 9th century. The castle, a masterpiece of medieval military architecture, played a strategic role in the defense of the area, thanks to its nine watchtowers, which made it possible to see enemy ships from a distance and to prepare the population against enemy attacks. An example of strategic ingenuity designed to withstand time and siege.

The castle, located on the hill between the districts of Accola and Carpineto, was actually a defensive fortress rather than a feudal residence. It was built after the death of Sicardo, Lombard Duke of Benevento (840), as a refuge against the incursions of the Lombards and later the Barbary pirates. The fortress was built around an ancient church dedicated to St. Nicholas of Thoro-Plano.

In 1461 the Piccolomini Dukes of Siena, appointed feudal lords of the Duchy of Amalfi by Ferdinand I of Aragon, enlarged and restored the fortress. The work, begun in 1465 and completed in 1468, cost six thousand ducats. The historian Michelangelo Gizzio described Maiori as an almost impregnable town thanks to the coastal towers armed with cannons and the very strong castle.

Inside the walls were barracks, warehouses, cisterns, and a water source, essential in case of siege. The castle could house a large garrison and numerous civilians. The structure, which is still well preserved, has a polygonal perimeter of about 550 meters, with walls equipped with loopholes and nine cylindrical towers eight meters high. It was visually linked to the fortress of San Michele Arcangelo on the nearby Torina hill, forming a strategic defensive system for the area.