Frederick II had built his Palatium in 1200 to control Saracens deportees from Sicily that he had moved to Lucera. Fortress itself, still visible, was instead built by Charles I of Anjou and completed in 1283. The whole area is an archaeological mine: an ancient site, where there are remains of Neolithic huts, ruins of Roman period, of Swabian and a church dedicated to St. Francis of Assisi. Palatium was a square complex that rose to three floors, developing around a central square courtyard, which at the third floor level had octagonal shape characteristic of Frederick's castles. Irregular boundary wall that encircles entire hill is 900 meters long and also consists of 13 square towers, two pentagonal bastions, 7 spurs and 2 cylindrical towers: Tower of Queen, embattled, and King's Tower.