THIBAUD, Pierre (tee-bo), French scientist, born in Pithiviers in 1739; died there in 1804. He was for many years a professor in Paris, and was also employed by the French academy of literature in making linguistic researches. In 1788 he was elected secretary of the Academy of Caen, but retired to his native city during the revolution. Thibaud devoted himself principally to the study of the migrations of men, to the descent of nations, and their travels through the world; he was also the first to advance the theory that the Indians of America migrated from Asia in remote antiquity, and through patient, research was enabled to give a nearly complete history of the Aztec nation since their first appearance in the basin of Mexico about 500 B. C. Thibaud's works contain some errors, but he was a pioneer in the field of Indian history. He published " Origine des Indiens de l'Amerique du Nord, contenant une description de leurs manieres, avec une etude sur leur religion, leur langage, et leur maniere de se vetir" (Caen, 1787) ; "Histoire et migrations de la nation Aztec ou Mexicaine depuis le cinquieme siecle de notre ere jusqu' a la chute de la dynastic de Montezuma" (1796) ; and "Origine des Indiens de l'Amerique du Sud.' (Pithiviers, 1801).