SACY, ISAAC LOUIS LE MAITRE DE (1613-1684), a figure of some prominence in the literary annals of PORT ROYAL (q.v.), and after the death of St Cyran (1643) and Singlin (1664) the leading confessor and " director " of the Jansenists in France, was born in Paris on 29th March 1613. He was closely connected with the Arnauld family, his true surname being Le Maitre and that of Saci or Sacy which he afterwards assumed a mere anagram of Isaac, his Christian name. He studied philosophy and belles lettres at the College de Calvi-Sorbonne, and afterwards, under the influence of St Cyran (see DTTITERGIER DE HAURANNE), his spiritual director, joined his eldest brother Antoine Le Maitre at Port Royal des Champs. Here he threw himself heartily into the life of the place, devoting himself specially to teaching and the preparation of school-books, his chief productions in this class being expurgated editions of Martial and Terence and a translation of Phdrus. In 1650 he was ordained to the priesthood, and in 1654 he entered the field of theological controversy with a brochure entitled Enluminures de l'Almanacli des Jesuites intitule la Deroute et la Confusion des Tansenistes, of which it is enough to say that, if the Jesuit attack was in execrable taste, neither was the reply in keeping with the finer ethical tone of Port Royal. From 1661, after the breaking up of the Petites Ecoles, he lived more or less in concealment in Paris until May 1666, when he was thrown into the Bastille, where he remained till November 1668. During his imprisonment he occupied himself with the completion of a new version of the New Testament, known as the Nouveau Testament de Mons (1667), and the remainder of his life was largely devoted to a similar translation of the Old Testament, based chiefly on the Vulgate, with Eclaircissements. These began to appear in 1672 and were continued down to the end of the minor prophets. As De Sacy knew nothing of Hebrew, this version is of no value as a contribution to scholarship, and in style it is more artificial and laboured than those which had preceded it. From 1668 till his death on 4th January 1684 he lived partly in Paris, partly at Port Royal des Champs, and partly at Pomponne, the seat of his cousin, the marquis de Pomponne. He was buried at Port Royal des Champs.

In addition to the works already mentioned, he published, under the pseudonym of the "Sienr de Beuil," a French translation of the De Irnilatioee Christi (1662). He also translated Chrysostom's Homilies on .31cathmo. See Sainte-Beuve, Port Royal, bk. ii. chaps. 17, 18 (ed. 1878).