Built on the model of the Crusader castles of the Holy Land, the castle has a quadrangular plan, reinforced at the top by four square towers of equal height. In the 16th century, with the advent of firearms, the castle was adapted to new defensive techniques and in the nineteenth century it was the subject of new restoration works that turned it into a prison. In 1970s it is handed over to the Ministry of Education today Ministry of Culture, which over the years has taken care of the restoration works and the museum creation. The building has two monumental halls on the first floor, from the Frederick era. This was further enlarged with the construction of bastions, one on the north – east side with a square plan and the one on the South-west side at the tip of the spear, connected by the wall that encloses large secondary courtyards. The body of the casemates, built in the Renaissance period, delimits the central courtyard.

The visit of the castle allows to understand, through the succession of the various rooms and courtyards, the juxtaposition of constructive – defensive techniques that made the castle in the Middle Ages of the most modern defensive bulwarks of the Swabian dynasty, then moving on to the Renaissance, with the thickening of the southern front and the construction of the ramparts, thus ending with the interventions of nineteenth century, with the detention cells and the clock tower. In the Museum, located on the ground floor of the square bastion, there are stone finds and ceramics from the excavations carried out during the restorations of the twentieth century.