Located at an altitude of over 400 metres on the slopes of an extinct volcano, Monte San Matteo, where one of its many places of worship stands. Ploaghe is a village in the Logudoro region with fewer than fifty thousand inhabitants, an episcopal see from 1090 to 1503 and a curatorial administrative centre in the Giudicale period. In the old town centre, there are the signs of a glorious past. Looking out onto a square, there is the Town Hall, once Monte Granatico, and an impressive Christian complex, in which the main building is the parish church of San Pietro Apostolo. The former cathedral, dating back to the 15th century, was refurbished several times. Then there are the oratories of Santa Croce (16th century) and of the Rosario (18th century) and the parsonage, where the art gallery is located and contains the Quadreria Spano: 26 paintings dating back to a period between the 14th and 19th centuries, collected by the scholar Giovanni Spano, including works of famous artists working in Sardinia or from various Italian regions, Flanders and Spain. The parish archives contain rare manuscripts, books and ancient documents.