It is an important witness to the system of surveillance and defence of the Campidano territory in medieval times and it is also literally surrounded by fascinating legacies from pre-Nuragic and Nuragic times. The castle of Baratuli stands on the top of Olladiri in the territory of Monastir and was built on a previous settlement dating back to the Bronze and Iron Ages. It was built around the middle of the 12th century in the name of the judges of Cagliari, with the aim of monitoring the southern part of the Campidano area. It later passed to the Gherardesca family, who also owned the castles of Acquafredda and Gioiosa Guardia between the current territories of Siliqua and Villamassargia. After the fall of Count Ugolino, one of the most famous and controversial characters of Dante’s Inferno, it ended up in the hands of the Republic of Pisa, which destroyed it in the early 14th century, perhaps to avoid it being conquered by the Aragonese. Along with the castle, the village of the same name located in the valley, near the country church of Santa Lucia, was also destroyed.