It is named after Cornelius Jansen, who was the Bishop of Ypres in the early 17th century. His main work, Augustinus, was published after his death. In this work, he claimed to have rediscovered the true teaching of St. Augustine concerning grace, which had been lost to the Church for centuries. Even though he was not strictly a heretic, his writings still caused great harm to the Church. At that time, the Jesuits were heavily preaching on the mercy of God. This was seen by some as moral laxity. Also the debates with the Calvinists had an influence on Jansen’s thoughts. Without going into the details of the “five propositions from Jansen”, this heresy essentially taught that God’s saving grace is irresistible, though not given to everyone. According to Jansen, a person could neither accept or reject this grace due to his fallen nature. Although persons, who received it, were sure of salvation. Unfortunately not everyone received this saving grace. God decreed who was saved and who was lost. Jansen denied human free will and God’s desire to save everyone (1 Tim. 2:4). Even though the Jansenists hoped to combat the moral laxity of their time through moral rigorism, their denial of human free will and God’s mercy actually promoted moral despair or a carefree, frivolous life style, since personal actions had no effect on personal salvation. Due to the duplicity of its promoters, this heresy harmed the Church for over seventy years.