In medieval times, the territory of Maranzana was controlled by the Marquis of Incisa.
In 1180 the Marquis Del Bosco entered into an agreement with Alessandria, receiving part of the Alessandria territory as a fief and, as a place of great strategic importance, the fief of Maranzana.
In 1221 the fief of Maranzana became property of the Astigiani who, swearing allegiance to the bishops, received the territory in exchange.
After intricate and alternating events, in 1477 part of the fiefdom passed to the Occimians and in 1590 Antonio di Biandrate became feudatory of the territory.
These, in 1634, alienated the castle of Maranzana to Filippo Caresana whose family, a few years later, passed the possession of the Ghilini family who, in turn, ceded the property to the Pozzi family during the nineteenth century.
The Maranzana castle is located inside the town's concentric, and the complex is a valid example of fortified construction and stands out for its grandiose and austere wall structure, lightened by some elements of architectural and decorative quality.
It is characterized by a large protective wall of strategic importance, overlooking the valley of the Cervino stream to the northwest and opening to the east to the concentric, by a bridge that was formerly "draw" and that even now allows access to castle.
From this side the walls close around the ancient tower (existing before the body of the castle) that repeats in its friezes, sawtooth, the ornamental motifs around the perimeter of the walls that dominate the central square.
At the end of the 16th century, a ditch surrounded the rainwater around the shelter.
The majestic construction has retained some important parts, despite the alterations carried out over time, including: the imposing square tower which has at its base a masonry and at the top a beautiful frieze, sawtooth; the large building that sits on the tower with an obtuse angle; the path of the curtains (about two meters of masonry) and the beautiful circular corner tower, also decorated with saw-teeth, but unfortunately remained the victim of a tampering, concerning a small loggia built in its upper part, obtained by destroying the crowning and the battlements.
In Maranzana, as well as in other Monferrato castles, it is interesting to point out a constant characteristic: the coexistence of square and round towers in the same manor.
The alternation of round and square towers in the castles of the area is hardly ever a coincidence, but one can safely say that it is a very precise style of construction, which consists of building, in general, the corner towers in circular form, while the keep or in any case the tower above the entrance in a square or rectangular shape.
This peculiarity rarely occurs in other regions of Italy.