The Church of San Pietro stands in the upper part of the town of Galtellì.
At the end of the XI century A.D., building work started, and was then interrupted due to a lack of funds, on the Cathedral of Galtellì, whose remains of the apse facade are still visible opposite the church porch of the Church of San Pietro.
Following the interruption to the work, the church of San Pietro housed the bishop’s chair until 1495, when the diocese of Galtellì was incorporated into the archdiocese of Cagliari.
Originally, the church layout included a crux commissa with a single nave hall. At the start of the XIII century, the walls were embellished with a cycle of frescoes, now mostly lost, following the construction of two side naves.
The frescoes, produced by workforces from Lazio, are arranged on two orders and show on the left, scenes taken from the Old Testament, and, on the right, scenes taken from the New Testament.
