ISOART, Louis (e-zo-ahr), Spanish missionary, born in Burgundy in 1599; died in San Jose, Paraguay, in 1640. He became a Jesuit in 1624, went to Buenos Ayres in the following year, and in 1627 was attached to the missions of the Care forests, between Yuvi and Piratini rivers. He found there about 500 Indian families, which he civilized and established in a village. Five years later his superiors sent him to a larger field of labor among the Tupi and Mamelo Indians, who had never yet permitted a European to cross their country, and were reputed the most warlike Indians of those regions. Isoart went alone to their forests, and, presenting himself to the cacique, told him he had come to make him a Christian. The courage of the missionary impressed the chief, and through his influence Isoart was enabled to establish missions. The Indians had so much confidence in him that they never recognized the laws of Spain, but lived for a century under the rule of Isoart. He left several manuscripts, which were afterward published in "Litterae annum provinciae Paraguariae Societates Jesu" (2 vols., Rome, 1646); "Relations et proges de la religion Chrdtienne faits au Paraguay" (1647); "Histoire, chroniques, et usages des Indiens Mamelos et Tupis" (1649); and several other works.