The story of Our Lady of Bonacattu begins in the 5th century, when the Byzantine settlers began building a small quadrangular church (12 metres each side) from basalt and trachyte rock. Subsequent alterations (7th-8th century) were made when the first nucleus of the present-day Bonarcado may have already been established, a village at the foot of Montiferru, 25 km from Oristano. The site of the little sanctuary, which was undoubtedly one of the earliest Christian buildings on the Island, has its roots in even more distant events, dating back to a Nuragic settlement on top of which a Roman village with a thermal bath building was built, the remains of which were used to build the sanctuary. A bath with mosaic flooring in the eastern ‘wing’ bears witness to this.

There are legends linked to the name: apparently, the church was discovered in the wood by a hunter and, in fact, the Sardinian name Bonacattu, meaning ‘a good find’.