Menno Simons (mĕn´ō sē´mōns), 1496?–1561, Dutch religious reformer. The name of the Mennonites was derived from his name, although he was not the actual founder of the sect. In 1524 he became a Roman Catholic priest but in 1536 he left the church when he announced that he no longer believed in infant baptism and other Catholic teachings. His test of the true Christian was regeneration. He was active in Holland and Germany as an organizer and leader of the less aggressive division of Anabaptists. His writings and sermons were published as Opera omnia theologica (1681).
See his Complete Writings ed. by J. C. Wenger (tr. 1956); C. J. Dyck, ed., A Legacy of Faith (1962); W. E. Keeney, The Development of Dutch Anabaptist Thought and Practice from 1539–1564 (1968).