The former French Catholic diocese of Saint-Papoul was created by a bull of Pope John XXII, issued on 22 February 1317. The seat of the diocese was at Saint-Papoul, in south-west France, in the modern department of Aude; it was some distance northeast of the main highway between Carcassonne and Toulouse, where there was already a Benedictine monastery, founded in the eighth century and dedicated to Saint Papoul. The bishop of Saint-Papoul was suffragan of the Archbishop of Toulouse.
The diocese existed until the French Revolution. It was one of the diocese scheduled to be suppressed under the Civil Constitution of the Clergy (1790). Under the Concordat of 1801 its territory was taken over by the diocese of Carcassonne.
Ancient Diocese of Saint-Papoul Wikipedia
In his bull of erection, Pope John XXII stated that the population in the diocese of Toulouse was growing at such a pace that the Bishop was no longer able to govern his people effectively; and that therefore, having consulted with the cardinals, he had decided to promote the diocese of Toulouse into an Archbishopric and Metropolitanate, with four new dioceses, one of which was Saint-Papoul.
The Benedictine abbey of Saint-Papoul was converted into the Cathedral, and the monks were organized into a Cathedral Chapter consisting of twelve Canons led by a Prior Major (rather than Dean or Provost, since they remained a monastic community). In 1670 the Chapter was converted into a college of twelve secular Canons, with a Provost and four prebendaries.
The Pope also made the church of Castelnaudary into a Collegiate Church of twelve Canons, with a Dean, a Sacristan, a Precentor; there were also to be three hebdomidary priests, 24 chaplains, two deacons and two subdeacons, as well as six clerics in minor orders.
In 1716, there were approximately 1,000 faithful Catholics in the town of Saint-Papuli, and the diocese contained forty-four parishes. In 1774 there were still approximately 1,000 faithful Catholics, owing temporal obedience to the King of France.