The castle under Ercole I

Obviously, they tried to change the austere rooms of the fortress into welcoming apartments and to create an area on the first floor (piano nobile) that was similar to their palace without interfering with the ground floor, that of the courtyard, where important functions aimed purely at the defence of the family's new castle home were still concentrated.
The Via Coperta, the Duke's new apartment, was extended, extensively decorated on the outside with frescoes, statues, and fake architectural features. The eastern wing of the castle doubled in size and at the same time the courtyard was changed and a new portico added. It was perhaps just at this time, when the courtyard became a courtyard of honour that the stables and many of the service workshops were moved into the large yards that surrounded the castle.
These sheltered under a primitive gallery which stood against the four sides of the castle, held up by large square pilasters. In 1483 Duke Ercole was helped in his work by Biagio Rossetti, the new court architect and the two brought into being a magic period in the city's development of architecture and town planning, which in the space of just a few years saw the city walls more than double in length and construction sites for streets, squares, palaces, churches and convents spring up everywhere.
The effects were also felt in the castle, which came to find itself at the centre of the city. Among the castles that history has conserved it is very rare to see one with such a central urban position. They have usually remained separated from the urban fabric, perched on high and in any case still evidently ready to assume the original function of defending the suburb of the city in a direct confrontation with potential enemy. Ferrara's Castello Estense, right at the centre of the town clearly remains a defensive building but also becomes an austere generating presence that radiates over the city through glimpses that lead to the castle no longer only dominating the panorama of the surrounding countryside but appearing in glimpses from the ends of the many roads that from the older and newer gateways lead to the centre. At that time decoration work was concentrated on Eleonora's apartment, which was near the Marchesana Tower towards the Torre dei Leoni, and it was Rossetti himself, in that part of the castle who began the construction of the Giardino degli Aranci (Orange Garden) and the building of the new Ducal Kitchens.