The pre-existent castle is well integrated with the more recent walls. It was in fact built by the Svevi but it was expanded and modified by the Angioni.
Out of the original four angular towers, only three remain. The Aragonesi themselves demolished the fourth tower at the south-east junction of the castle in 1540, in order to allow the construction of the rafter in the new city walls. The complex was close to a fifth tower, called " the Norman tower", approached through a drawbridge.
Inside the castle you can see the "palatium" and the beautiful romanesque church of "S. Giovanni in castro". The church has been carefully restored to its former splendour and original architectural features, thanks to careful refurbishment.
Built in the second half of the twelth century, only later was it included in the circuit. Tt has only one nave with a front cuspidal and a small steeple and ceiling in a style called "a chiancarelle".