 The architect Girolamo da Carpi gave the castle the external appearance which can be still seen today, although the interior has been remodelled several times across the ages.After the departure of the Este to Modena, the castle became the residence of the Papal Legate who administered the Ferrarese territory as civil governor (for a maximum term of four years).There were few changes made to the structure of the building, the most obvious being the increase in height of the north ravelin (the room which currently houses the cafeteria).