Once the Reconquest of Spain from the Moors had started, the king Sancho el Mayor from Navarra organised a defensive system of castles and towers which visually communicated between them. The tower was built by Lombard master builders in the 11th century on top of an older plinth of possible Arab origin. The building is of great quality divided into five floors crowned by a wooden projection with a corridor which surrounds the perimeter of the tower. The entrance is located on the first floor accessed through a wooden staircase. Not only it was a defensive tower, but it was also used as a lodging during siege. The lavatory and the chapel are still there. The rest of this medieval construction is composed of walls which closed the defensive grounds and a Romanesque church that conserves its apse.