BOURG-EN-BRESSE, DIOCESE OF. – The chief town of the department of Ain on the left bank of the river Reyssouze; it was erected in 1515 at the request of Francis I, but the bull was revoked the following year; it was re-established in 1521 at the request of Charles V by Leo X, who assigned to it the territories of the Bresse, the Dombes and the county of Burgundy, which until then had belonged to the diocese of Lyon. It was suppressed in 1534 by Paul III, who assigned it to Lyon, whence it passed to Belley in 1822.
The oldest parish of B. was the priory of St Peter of Brou, dating from the mid-11th century, situated one km to the south of B.; only the 15th-century cloister remains. The church was rebuilt by Margaret of Bourbon and consecrated in 1522; it is in Gothic style with three naves and contains the tombs of the foundress, of her husband Philip the Fair and of Margaret of Austria, and is dedicated to St Nicholas of Tolentino. Also in Gothic style is the interior of the church of Notre-Dame, begun in 1505, continued in the 17th century and completed in the 19th; and also the abbey of the Poor Clares founded in 1402 by Amadeus I of Savoy.