Fitzsimon, Henry a zealous Jesuit, was born at Dublin in 1569, educated at Oxford, and died in 1644. He published a Justification of the Mass (1611): — a Catalogue of the Irish Saints (1621), and some other theological treatises in defence of his faith. See Chalmers, Biog. Dict. s.v.; Allibone, Dict. of Brit. and Amer. Authors, s.v.