The monument is located in the southern part of the Gerrei plateau, northeast of the town of Silius. The castle dates back to the 12th century, when it was erected by the Giudici of Cagliari to defend the borders with the Giudicato of Arborea. Referred to by Fara as Orguloso, it was later called Sassai Castle.
Of its history it is possible to trace a brief outline because of the scarcity of written sources. In 1353 it was attacked by the partisans of Mariano d’Arborea, during the war against the Aragonese.
Fara states that the Sardinians who besieged and took the Orguglioso Castle were almost all from Cagliari, partisans of the Giudice d’Arborea. Also according to Fara, the castle had seven hundred horsemen and numerous infantry. Given as a fief to the Carroz in 1355, it was demolished by Judge Mariano. In the drawing made by the Aragonese in 1358 the castle of Argullos, so indicated by them, now appears ruined. Reduced to a heap of ruins until not too many years ago, the monument has now been resurrected thanks to restoration work conducted by the Municipality of Silius in collaboration with the Superintendence for Architectural, Landscape, Historical, Artistic and Ethno-anthropological Heritage of Cagliari and Oristano.
Much of the structures have been brought to light by archaeological excavations. A cistern and a bread oven were found among the walls. In addition to the perimeter and dividing walls and a square-section tower, two vaulted underground rooms with some iron rings on the walls, possibly used as prisons, stand out.
