Boniface of Savoy was a medieval Bishop of Belley in Savoy and Archbishop of Canterbury in England. He was the son of Thomas, Count of Savoy and owed his initial ecclesiastical posts to his father. Other members of his family were also clergymen, and a brother succeeded his father as count. One niece Eleanor of Provence was married to King Henry III of England, and another was married to King Louis IX of France. It was Henry who secured Boniface's election as Archbishop, and throughout his tenure of that office, he spent much time on the continent. He clashed with his bishops, with his nephew-by-marriage, and with the papacy but managed to eliminate the archiepiscopal debt that he had inherited on taking office. During Simon de Montfort's struggle with King Henry, Boniface initially helped Montfort's cause but later supported the king. After his death in Savoy, his tomb became the object of a cult, and he was eventually beatified in 1839.

The Diocese of Belley–Ars is a Latin Church ecclesiastical jurisdiction or diocese of the Catholic Church in France. Erected in the 5th century, the diocese was renamed in 1988 from the former Diocese of Belley to the Diocese of Belley–Ars. Coextensive with the civil department of Ain, in the Region of Rhône-Alpes, the diocese is a suffragan see of the Archdiocese of Lyon. The cathedra of the bishop is at Belley Cathedral. The current bishop is Guy Claude Bagnard, appointed in 1987.