- Population: about 9,000 inhabitants
- Zip/postal codes: 091013
- Dialing Area Code: +39 0785
- Patron Saint: Sant'Emilio e Priamo, celebrated on 28 May
- Frazioni & Localities: Bosa Marina
In the 14th century the castle, under Mariano d'Arborea, was a stronghold against the Aragonese invasion. In 1388 the town acquired an almost unique status, partly independent of feudal dominion, and had its own magistrate, called podestà. In 1499 king Ferdinand the Catholic awarded Bosa the honor of being a royal town, though the castle was still under a feudal lord, the Villamari Admiral. Throughout the Middle Ages, there was a thriving commercial and artisan community in this strategically important center.
What to see
- The Serravalle Castle, built starting from 1112, when some of the towers were erected, was later enlarged, and in 1330 had a perimeter of 300 meters, with seven towers.
- The church of Regnos Altos, in the square of the Castle, with inside a fine fresco cycle of the 14th century representing in each scene the Franciscan virtues: charity, chastity, humility, heroism against evil, courage in martyrdom, admonition for a good death. A unique scene represents the meeting of three living and three dead.
- The ancient Cathedral of San Pietro, built starting from 1062 - the date is inscribed in a stone inside; in the 12th century the apses were built and the 13th century other additions followed in the French Gothic style. The facade, a project by Anselmo from Como, contains three rose-windows and on the portal the statues of St Peter, St. Paul, the Virgin with Child, St. Constantine, in honor of the bishop Costantino de Castra that founded the church.