From 1309 to 1522, the Knights of St. John, a Christian military organization, ruled the island of Rhodes. In the early 14th century, they made numerous modifications and converted the Byzantine citadel into an administrative center and the residence of their Grand Master.
It was during the Italian occupation in 1937 that extensive restoration works were carried out. Between 1937 and 1940, the Italian architect Vittorio Mesturino rebuilt it to become a holiday residence for King Victor Emmanuel III, and later for the dictator Benito Mussolini. Since the return of the island in 1948 to the Greeks, the palace is a museum.
After the Ottoman occupation of Rhodos in 1522, the building lost its importance and was mainly used as a prison. Several earthquakes progressively damaged the building until, in 1865, a devastating explosion in the nearby basement of the church of St. John, used as an arsenal by the Ottomans, turned the Palace in a mass of ruins. The first floor collapsed completely, and very little of it survived until 1937, and the beginning of restoration work.
The Palace has very imposing dimensions and defensive fortifications.