Excavations regarded the “posterula” sector outside the castle’s south wall. Traces of the earliest buildings were recorded here dating to the Byzantine period (in particular the 9th-11th centuries A.D.). A large, square tower was uncovered associated with a cistern and silos which were probably in use until the construction of the Svevan keep.
The Byzantine structures were abandoned by the Normans who built a new, large rectangular enclosure. Successively the period of Fredric II saw the construction of a low curtain wall to the south and west of the keep. Subsequently the perimeter curtain walls were raised to about the height at which they stand today, thus annulling the keep’s function, which was probably only kept for its cistern. The eastern part of the courtyard, housing the baths, built partly re-using the earlier Norman foundations, was radically restructured. The entire lower floor of the east wing was occupied by activities connected to the balneum. (Maria Luisa Nava)