See K.H. Klaiber, _Henri Arnaud, ein Lebensbild_ (Stuttgart, 1880); A. de Rochas d'Aiglun, _Les Vallées vaudoises_ (Paris, 1881); various chapters in the _Bulletin du bicentenaire de la glorieuse rentrée_ (Turin, 1889). (W. A. B. C.)
ARNAULD, the surname of a family of prominent French lawyers, chiefly remembered in connexion with the Jansenist troubles of the 17th century. At their head was ANTOINE ARNAULD (1560-1619), a leader of the Paris bar; in this capacity he delivered a famous philippic against the Jesuits in 1594, accusing them of gross disloyalty to the newly converted Henry IV. This speech was afterwards known as the original sin of the Arnaulds.
Of his twenty children several grew up to fight the Jesuits on more important matters. Five gave themselves up wholly to the church. HENRI ARNAULD (1597-1692), the second son, became bishop of Angers in 1649, and represented Jansenism on the episcopal Bench for as long as forty-three years. The youngest son, ANTOINE (1612-1694), was the most famous of Jansenist theologians (see below). The second daughter, ANGÉLIQUE (1591-1661), was abbess and reformer of Port Royal; here she was presently joined by her sister AGNES (1593-1671) and two younger sisters, both of whom died early.
Only two of Antoine's children married--ROBERT ARNAULD D'ANDILLY (1588-1674), the eldest son, and CATHERINE LEMAISTRE (1590-1651), the eldest daughter. But both of these ended their lives under the shadow of the abbey. Andilly's five daughters all took the veil there; the second, ANGÉLIQUE DE ST JEAN ARNAULD D'ANDILLY (1624-1684) rose to be abbess, was a writer of no mean repute, and one of the most remarkable figures of the second generation of Jansenism. One of Andilly's sons became a hermit at Port Royal; the eldest, ANTOINE (1615-1699), was first a soldier, afterwards a priest. As the Abbé Arnauld, he survives as author of some interesting _Memoirs_ of his time. The second son, SIMON ARNAULD DE POMPONNE (1616-1699), early entered public life. After holding various embassies, he rose to be foreign secretary to Louis XIV., and was created marquis de Pomponne. Lastly Madame Lemaistre and two of her sons became identified with Port Royal. On her husband's death she took the veil there. Her eldest son, ANTOINE LEMAISTRE (1608-1658), became the first of the _solitaires_, or hermits of Port Royal. There he was joined by his younger brother, ISAAC LEMAISTRE DE SACI (1613-1684), who presently took holy orders, and became confessor to the hermits.