Martin de Barcos

Barcos was born at Bayonne, a nephew of Jean du Vergier de Hauranne, the commendatory abbot of the Abbey of Saint-Cyran-en-Brenne in the Duchy of Berry, who sent him to Belgium to be taught by Cornelius Jansen.

When he returned to France he served for a time as tutor to a son of Robert Arnauld d'Andilly and later, in 1644, succeeded his uncle as the owner of the abbey.

Unlike many commendatory abbots of his day, however, who scarcely ever saw the monasteries over which they held authority, Barcos became an active member of the abbey, became a priest in 1647, and gave himself up to the rigid asceticism preached by his sect.

Barcos' ties with Du Vergier and Arnauld and, through them, with the Abbey of Port-Royal-des-Champs, soon brought him to the front in the debates about Jansenism.

This theory of dual church authority, implying an equality of the two apostles, was condemned as heretical by Pope Innocent X in 1674 (Denzinger, Enchiridion, 965).