The fortress was built by the family Acquaviva in 1300, but few traces remain of the original. In 1447 the fortress underwent full-bodied primitive faults from Fermo, who held in Acquaviva fundamental strategic interests. It was rebuilt in 1474 by Giovan Francesco Azzolino, and the work was directed by the Florentine Baccio Pontelli. Un other general restoration was made by Giuseppe Sacconi and was completed at the end of the nineteenth century. Research carried out since 2004 have made it possible to reconstruct the original image of the century fortress. In the Middle Ages it had an octagonal tower and walls of considerable elevation with Ghibelline battlements. In the transition to the modern age, following the introduction of firearms, the fortress was established thanks to the thickening of the walls and towers, the addition of a triangular shoe and the external reinforcement of the keep which assumed a cylindrical shape. A active defense were created gunner and sharpshooter, in addition to various Pusterle and patrol galleries. The fortress, which is supposed to be surrounded by a moat, covers a wide central court served by a well. The plant is an irregular quadrilateral, culminating in a tower at each vertex. The towers have different size and consistency orography of the terrain and the risk of external attacks. The cylindrical tower is 22 m high. The main tower on the opposite side has the guns, while the other two were for lightweight artillery The interior of Rocca d'Acquaviva houses the Museum of Pajarole and the Museum of Ancient Arms.