Among the fortifications commissioned by Pope Innocent VIII towards the end of the 15th century, in order to give solidity to papal power, the Rocca di Offida was commissioned to the Florentine architect Baccio Pontelli, his relative, who already boasted the designs of several fortresses in the brand, as in Osimo and Jesi.
The project was carried out by Comancine workers and included, in addition to the construction of the fortress, also the restoration of the previous fortifications. The arilleries were commissioned in 1492, and after the fortress lost its importance, they were brought to Loreto for the defense of the Holy House, where they are still preserved. With a vaguely pentagonal plan, visible in an illustration from the end of the seventeenth century, it is characterized by two cylindrical towers, the largest of which was probably the keep, and by a square tower that protrudes slightly from the wall line. In ancient times it was also surrounded by a moat filled with water.
On the western side there is also a small square turret, at the junction between the fortress and the walls, which also guards a small secondary door for the exclusive use of pedestrians, located at a certain height from the ground; it is equipped with a staircase that immediately after the entrance turns 180 °, while a musket slot located in front of the entrance, could target anyone who had crossed the threshold.
Of great interest is the main cylindrical tower, which flanks the current city entrance and where it is possible to find the coat of arms of Pope Innocent VIII. By reusing the previous square tower of the city gate, a protective brick mantle was created which transformed it into a squat round tower equipped with housing for artillery.
Interesting is the row of corbels that crowns the top, each of these has a hole where a wooden parapet was installed to protect the upper platform, a rare expedient as they were very often made of masonry. The inner side of the tower is open and you can see the remains of the medieval gate with the entrance arch and the sliding seat of the portcullis.
At the beginning of the twentieth century the rooms had been transformed into an aviary to guard an eagle, the pride of the town. Only a few traces of the battlements that ran along the ramparts survive: three solitary dovetail battlements overlooking the northern front, in front of the lacemaker fountain.
In 1796 the architect Pietro Maggi was commissioned to build the new hospital, which still exists today, to unify the existing ones of the Santissima Trinità di Sant'Antonio abate; it was decided to erect it in the area of the fortress, demolishing the fortifications inside the city walls.
The remains of the fortress, so dear to the inhabitants of Offida, still continues to provide its scenic support to the beautiful town of the Marche rich in art and history.