The ancient cathedral of Bosa was built between 1062 and 1073 over the ancient Roman settlement situated 2km east of the modern-day town on the southern bank of the Temo River. All that remains of the original structure in Lombard Romanesque is the central aisle, later combined over two centuries with an apsis, bell tower and Gothic-Cistercian inspired façade in pink trachyte. The limestone relief sculpture on the portal portrays the Virgin Mary with Child, the Saints Peter and Paul and the emperor Constantine, worshipped in Sardinia under the name of Santu Antine: legacy of the Byzantine occupation after the fall of the Roman Empire.