Dubois, John(1764–1842) Catholic prelate; born in Paris, France. Ordained in 1787, he emigrated to the U.S.A. during the French Revolution, ministered to widely scattered Catholics in Virginia, and founded Mount St. Mary's Seminary in Emmitsburg, Md. (1809), a training ground for early Catholic church leaders. He also helped establish and guide the Sisters of Charity, founded by Mother Seton. In 1826 he became the third bishop of New York.