BOURG-EN-BRESSE, DIOCESI di. — Capital of the Ain department on the left bank of the Reyssouze River; it was erected in 1515 at the request of Francesco I, but the bull was revoked the following year; it was re-established in 1521 at the request of Carlo V by Leone X, who assigned to it the territories of Bresse, Dombes, and the county of Burgundy, which until then had belonged to the diocese of Lione. It was suppressed in 1534 by Paolo III, who assigned it to Lione, from which it passed to Belley in 1822.
The oldest parish of B. was the priory of St-Pierre-de-Brou, dating from the mid-eleventh century, situated one kilometre south of B.; only the fifteenth-century cloister remains. The church was rebuilt by Margherita di Borbone and consecrated in 1522; it is in the Gothic style, with three naves, and contains the tombs of its founder, her husband Filippo il Bello, and Margherita d’Austria; it is dedicated to S. Nicola da Tolentino. Also Gothic in style is the interior of the church of Notre-Dame, begun in 1505, continued in the seventeenth century, and completed in the nineteenth; as is the abbey of the Poor Clares, founded in 1402 by Amedeo I di Savoia.
B., Paris 1917; A. des Mazis, Brou, in DHG, X, col. 855; L.-H. Cottineau, Répertoire topo-bibliographique des abboyes et priemés, I, Mâcon 1939, cols. 513–15.