It stands isolated on a small hill near the banks of the Tirso river and was built on the remains of a trefoil nuraghe, presumably in the mid-12th century, six kilometres from Bultei, the territory in which it is located, and six from Benetutti: the parishes of both Goceano villages claim ecclesiastical jurisdiction over it to the diocese of Ozieri. The church of San Saturnino owes its fame to its simple Romanesque architectural forms and also to the landscape and the archaeological value of the site where it stands. The first news of the sanctuary of Sancti Saturnini de Usolvisi dates back to 1163, the year in which it was donated to the Camaldolese monks - who had also built the stupendous Basilica of Santissima Trinità di Saccargia - by Attone, bishop of Castra. An early Christian inscription on stone, found in 1957, refers to the Byzantine age, suggesting the antiquity of the sacred place, the spiritual centre of a small village (that later disappeared) of Usolvisi, which developed continuously as a settlement along with the nearby Roman baths of Aquae Lesitanae. On the plain of San Saturnino, eight springs of thermo-mineral water with beneficial and curative properties have been counted and are partly exploited by the present-day thermal establishments. In addition to the ruins of the nuraghe, recent excavations on the plain have also unearthed pre-Nuragic remains and Roman ruins.

The perfect wall surface of the small building was made using perfectly-squared trachyte ashlars. Their reddish colour gives the monument an unusual appearance, accentuated by its slightly elevated position. The use of local red stone and the art in the placing of the blocks are clear signs of the ‘hand’ of Tuscan workers, perhaps the same ones who worked in the nearby Nostra Signora di Mesumundu at Anela, also donated to the Camaldolese by Bishop Attone. The corners of the linear Romanesque façade are reinforced by sturdy corner pilasters. In the centre, there is the architraved portal with a stilted arch and the same pattern is repeated in the side portal. Three single-lancet windows, two rounded arches on the sides and one in the curve of the apse light up the single nave, which is also made from slabs of volcanic stone from local quarries and covered by wooden trusses. A bell gable, which may have originally been on the façade, is now at the back of the building, above the apse.

In the church ‘contested’ between the parishes of Benetutti and Bultei, a mass is celebrated to honour the saint on 30 October. Regarding the dispute, which started between the end of the 19th and the beginning of the 20th century, in 1870 the historian Giovanni Spano already spoke about “a village called Bulterina with a parish church called San Saturnino”. It all began with the death of a parish priest in Bultei who, while on his way to celebrate mass in the church, lost his life wading across the Tirso river. After that, the key to the church was handed over to the parish priest of Benetutti, on the other side of the river, to safeguard the parish priests of Bultei and allow it to be opened safely. Since then, the keys have remained in Benetutti, without any episcopal act either then or now.