The Castle of Maiori appears on the summit of the hill which dominates the villages of Accola and Carpineto.
In reality the old ruins cannot be considered a castle literally, but a protected and entrenched area as well as the jurisdictional centre of a feudal Lord. It consisted of a rock, a fortress erected as a bulwark and refuge for the population in case of collapse of S. Sebastiano bulwark. It is worth mentioning that Thoro-plano means a knoll, a rolling hill, as opposed to the Thorus clivus, a steep hill which today is commonly called Torina or Tuoro, and corresponds to the area where in the 9th century there was the rock of St Michele the Archangel. The position of the two rocks granted an emergency signal system. According to the historic Cerasuoli the construction began a few years after the death of "Sicardo" a Lombard Duke of Benevento in the year 840. "Sicardo" had in the preceding year (839) devastated and pillaged the villages on the Amalfi Coast. The fortress was built around an ancient church dedicated to S. Nicola de Thoro-Plano. However the building in its current shape was reconstructed and enlarged by the Duke of Piccolomini (a family from Siena) which in 1461 was nominated by Ferdinando I of Aragona as feudal Lord of the Amalfi dukedom. The final construction was begun in 1465 and completed in 1468. The fort contained an antique church with three vaults and bell-tower, dedicated to S. Nicola de Thoro-Plano.
With reference to the Castle of Thoro-Plano, it is opportune to add that inside the fortified perimeter there were once barracks and shelters able to house a large battalion and hundreds of citizens seeking shelter. There were also stores and water cisterns on the western side and there was a spring in front of the Fossa Lupara (Santa Caterian) which guaranteed the water supply in case of a long siege. The building, as it appears currently, still preserves its original form with a polygonal perimeter which continues for 550 metres. The battlements equipped with spyholes and buttreses are separated by nine small cylindrical towers approximately 8 metres high with a diameter of 5 metres.