The Monreale Castle stands on a hill formation south of Sardara; an area which strategically offered an extensive view over the surrounding valley. The castle was built between 1206 and 1309, to defend the border between the Giudicato di Arborea and the Giudicato di Cagliari; it was part of a defence line which also incorporated the castles of Marmilla and Arcuentu.
Following the fall of the dominations into the hands of the Hispanics, the castle lost its defensive function and in the XV century became part of the properties of the Counts of Quirra. Following the death of the last family heir, the castle fell into a state of abandonment, while the population of the town moved to nearby Sardara.
The fortified complex included the quadrangular fortified tower, the defence wall with eight quadrangular and semi-circular defence towers, wells and cisterns, different service rooms and the town below. The layout of the entire defence wall is still visible to this day; the perimeter walls of the castle, however, are still standing.