Cornelius Jansen (1585-1638) was born in Gelderland in the Netherlands. In 1602 he began studies at Louvain, which was divided between the more morally rigorous Augustinians and the casuistic Jesuits. There, he befriended Jean du Vergier de Hauranne, better known to history as the Abbé de Saint-Cyran. They duly rose up the ecclesiastical ladder – the Abbé becoming chaplain at the strict and socially prominent convent of Port Royal, and Jansen being appointed Bishop of Ypres. During this time, the argument between the Jesuits and the Augustinians intensified; Jansen weighed in on the latter side, writing a book called Augustinus defending his views. Then he died.