Bisarchio, Diocese of, situated in Sardinia, in the province of Sassari, district of Nuoro, and suffragan to the Archdiocese of Sassari. The episcopal residence, however, is at Ozieri. Nothing is known as to the early history of Christianity in either the city or Diocese of Bisarchio. The first bishop mentioned is Costantino Madrone (c. 1102), who was succeeded in 1116 by Bishop Pietro. The bishop’s residence was changed several times, once to Giracle, and again to Ardera. In 1503, at the death of Fra Calcerando, bishop of this see, Bisarchio was incorporated into the Diocese of Alghero. The diocese was reestablished by Pius VII in his Bull of March 9, 1803, and bestowed upon Giannantioco Azzei, who in 1819 was promoted to the archiepiscopal See of Oristano, his native place. The episcopal residence was then definitely transferred to Ozieri. The cathedral, built in 1153, is well planned.
The Diocese of Bisarchio contains 24 parishes, 116 churches, chapels, and oratories, 78 secular priests, 25 seminarists, and a population of 40,000.