Cornelius Otto Jansen, (born October 28, 1585, Acquoi, near Leerdam, Holland--died May 6, 1638, Ypres, Flanders, Spanish Netherlands [now in Belgium]), Flemish leader of the Roman Catholic reform movement known as Jansenism. He wrote biblical commentaries and pamphlets against the Protestants. His major work was Augustinus, published by his friends in 1640. Although condemned by Pope Urban VIII in 1642, it was of critical importance in the Jansenist movement.EducationJansen entered the University of Leuven (Louvain), in the Spanish Netherlands in 1602 to study theology. According..