Roman Catholic Archdiocese of Rennes Tags: Clerical Administrative Region, Diocese.The Roman Catholic Archdiocese of Rennes (Lat:Archdiocesis Rhedonensis) is a diocese of the Latin Rite of the Roman Catholic church in France. The diocese is coextensive with the department of Ille et Vilaine. thumbnail area (km2) 6.775e+09 country France Established United: 13 February 1880 patron Saint Peter province Rennes Learn more... Loading...