She was born Jeanne-Catherine-Agnès Arnauld, a member of the Arnauld family, sister of Antoine Arnauld, "le Grand Arnauld" and of Mother Angélique Arnauld. She succeeded Angélique as head of the abbey in 1658, thus leading it during the most repressive anti-Jansenist period. She organised the movement against signing the Formulary of Alexander VII and for this was confronted by Hardouin de Péréfixe, the Archbishop of Paris. She was also the author of the Constitutions of Port-Royal, a text which reformed the material and spiritual rule of the abbey in a spirit of Cistercian renewal.
Perle Bugnon-Secrétan, Mère Agnès Arnauld. 1593 - 1672. Abbesse de Port-Royal, Cerf, 1996, 272 p.