The church of St. Peter was rebuilt beginning in 1821 in late Baroque form over the older Romanesque cathedral of 1144, commissioned by Mariano I, the seat until 1503 of the diocese of Terralba.
The present church has a Latin cross plan, characterized by a central nave with three chapels on each side and a facade adorned with pilasters topped by reused marble capitals from ancient buildings. On August 9, 1933, at the Diocesan Eucharistic Congress, the church was consecrated. Interior decorations depicting the four evangelists and St. Peter on the back wall of the chancel were made in 1951. The parish church houses capitals from Neapolis (an ancient Phoenician-Punic city) that were recovered during the demolition of the apse of the former cathedral. The baptismal font from 1626, the 17th-century wooden pulpit and a very valuable Spanish silver cross are preserved.
The wooden statues of St. Peter, Our Lady of the Rosary and Our Lady of Remedy also date back to the 17th century. In the 2000 restoration, the following were restored to their original appearance: the flooring, the walls, and the chapel dedicated to Our Lady of the Rosary.
