MOURAILLE, Theodore Gustave (moo-ri), Flemish explorer, born in Charleroi, Belgium, in 1594; died in Bahia, Brazil, in 1651. He became a Jesuit, was employed for several years in the Peruvian missions, and in 1631 began a voyage of exploration through the then unknown countries that are watered by the Amazon. Crossing the Andes to the head-waters of that river, he descended it as far as the Nape, and, turning southward, advanced about 500 miles into the interior. Returning to Quite in 1638, he joined the expedition of Pedro Texeira, guiding him in territories that he had been the first to explore. Drifting down the Amazon river, they reached Para in the autumn of 1639. Cristobal d'Acunha went immediately to Cadiz to publish the relation of the expedition, while Mouraille returned to Quito across the continent with only two negroes and four Indians. He went afterward to Bahia, where he became rector of the college of the Jesuits, and at his death was provincial of the order, he published "Describimiento de las Provincias del Rio de las Amazonas " (Quito, 1647).