The site of Vilhena Palace has been inhabited since ancient times, and post-Punic remains have been found in the area. In around the 8th century, a Byzantine fort was probably built on the site, and in the Middle Ages it developed into a castle known as the "Castellu di la Chitati". The castle's inner walls were demolished in the 15th century, and the remaining part was built up as a palace by Grand Master Philippe Villiers de L'Isle-Adam in the 1530s. The palace was called the "Palazzo Giuratale", and it housed the civil administrative council known as the Università. The structure was damaged in the 1693 Sicily earthquake.