The Norman Castle of Montescaglioso was built at the end of the 11th century as a control of Porta Maggiore. Erected by the Maccabeo, the castle is arranged around a courtyard which is accessed by a portal flanked by two towers of which one still exists. In the east wing the tallest tower is conserved, with a quadrangular plan, rendered unrecognizable by recent transformations. The church of Santa Caterina is annexed to the castle. On the ground floor there are cisterns, deposits, a hanging garden, stables and a porch, currently closed.
The castle was owned by various feudal lords of the country. At the beginning of the seventeenth century, acquired with the fief by the Grillo family, the stronghold was transformed into a comfortable palace. Restored, in 1857 the arm connecting the building to Porta Maggiore was demolished and the facade on the Corso was rebuilt in a neo-medieval style, with battlements and garritis. Between 1960 and 1964, the entire southern wing and one of the two entrance towers were demolished.