Jansen, Cornelius Otto 1585-1638
Dutch Roman Catholic theologian, and founder of the Jansenist reform movement

Born in Acquoi, near Leerdam, he studied at Utrecht, Louvain and Paris and became Professor of Theology at Bayonne and in 1630 at Louvain. In 1636 he was made Bishop of Ypres. He died just as he had completed his great work, the Augustinus, which tried to prove that the teaching of St Augustine against the Pelagians and semi-Pelagians on grace, free will and predestination was directly opposed to the teaching of the Jesuit schools. On its publication in 1640 the Augustinus caused an outcry, especially amongst the Jesuits, and it was prohibited by a decree of the Inquisition in 1641. In the following year it was condemned by Urban VIII in the Bull In Eminenti. Jansen's adherents included Antoine Arnauld, Blaise Pascal and the Port-Royalists. The controversy raged in France for nearly a century, when a large number of Jansenists emigrated to the Netherlands. The Utrecht Jansenists are in doctrine and discipline strictly orthodox Roman Catholics, known by their countrymen as Oude Roomsch (Old Roman).