[2] Legends which do not antedate the ninth century concerning Saint Caprasius, martyred with St. Fides by Dacianus, Prefect of the Gauls, during the persecution of Diocletian, and the story of Vincentius, a Christian martyr (written about 520), furnish no foundation for later traditions which make these two saints early bishops of Agen.

In the Agennais in the early medieval period, it was the duke of Aquitaine rather than the canons who had the decisive voice in the choosing of a bishop.

This can be inferred from the charter granted in 1135 by King Louis VII, the husband of Eleanor of Aquitaine, which restored to the canons of the chapter of Saint-Étienne the freedom to elect a bishop of their choice.

The cathedral chapter of Agen was reestablished in the Church of Saint-Caprais by Bishop Jean Jacoupy in 1802, by virtue of an apostolic brief of 10 November 1802.

[8] But on 29 September 1477, King Louis XI wrote to the chapter, announcing that he had named Jean de Monchenu to the bishopric of Agen, relying no doubt on the Pragmatic Sanction of Bourges (1438).

[9] Pope Sixtus IV, however, in a bull dated 4 October 1477, appointed his nephew Galeotto Grosso della Rovere as Bishop of Agen.

But on 14 November 1478, Pierre Dubois retracted his resignation, and on 9 April 1479, King Louis referred the entire matter, first to the Parlement of Bordeaux, and then to the Royal Council.

[17] During the French Revolution the diocese of Agen was suppressed by the Legislative Assembly, under the Civil Constitution of the Clergy (1790).

The new Civil Constitution mandated that bishops be elected by the citizens of each 'département',[19] The salaries were paid out of funds realized from the confiscation and sale of church properties.

[20] This system immediately raised the most severe issues in canon law, since the electors did not need to be Catholics and the approval of the Pope was not only not required, but actually forbidden.

Since the legitimate bishop of Agen, Jean-Louis de Bonnac, had refused to take the oath to the Constitution, his seat was declared vacant, and an election was ordered.

The carefully chosen electors of Lot-et-Garonne met, and on 13 March 1791 chose the Lazarist priest Labarthe, who was the director of the local seminary as their Constitutional bishop.

The electors of Lot-and-Garonne then seemed prepared to pick the titular bishop of Babylon, Jean-Baptiste Dubourg-Miroudot, but Andre Constant, a Dominican professor of theology from Bordeaux, had his name put forward by the Société des Amis de la Constitution.