Chiusi-Pienza, Diocese of (CLUSINENSIS ET PIENTINENSIS), suffragan of Siena. Chiusi is an important town in the province of that name in Tuscany. It is the ancient Clusium, one of the twelve cities of the Etruscan Confederation. Even yet many vestiges of Etruscan fortresses and tombs are visible. At an early period it became subject to the Romans. The Gospel, it is said, was preached there by the immediate disciples of the Apostles. Better authenticated, however, is the story of the martyrdom of the deacon Irenicus and the virgin Mustiola, which probably took place under Valerian, not under Aurelian. Catacombs are found at Chiusi. The first known bishop was Florentius, present in 465 at the Roman synod under Pope Hilary. Bishop Francesco degli Atti (1348) was a famous canonist, and died in the odor of sanctity. Chiusi formerly boasted of a famous relic, the betrothal ring of the Blessed Virgin, which was taken to Perugia about 1449 by an Augustinian friar; in consequence of this a war broke out between them, in which Perugia was victorious and remained in possession of the ring. Chiusi was at first immediately subject to the Holy See, but was made a suffragan of Siena by Pius II. In 1773 Clement XIV added to it the Diocese of Pienza. Among the famous abbeys of the diocese was that of Ammiato, which was built by Rachis, King of the Lombards, and afterwards rose to great power and influence. The diocese has a population of 26,300, with 56 parishes, 125 churches and chapels, 91 secular and 50 regular priests, 4 religious houses for men and 7 for women.