Jansenism is a branch of Catholicism that is based on the belief that human beings are born sinful and will never become good without assistance from the divine. Original sin, the depravity of all human beings, predestination, and the necessity of divine grace are cornerstones of Jansenism. The branch was formed based on the writings of Cornelius Otto Jansen, who was a Dutch theologian who lived from 1510-1576. Jansen opposed his contemporary Jesuit theologians on a number of issues. He focused on the work of St. Augustine of Hippo, and based his writings on principles which he perceived therein. His work, Augstinus, was not published until 1640.

The Jansenism movement within the Roman Catholic Church lasted from the 16th century to the 18th century. However, most of the movement occurred after the death of Cornelius Otto Jansen. Jansenism was condemned as heretical by a number of papal bulls, which are charters issued by the pope. Although a number of popes issued papal bulls against Jansenism, it was St. Pius X who finally condemned the movement. Jansenism was outlawed by the Catholic Church in 1712. Because the father of the movement was not alive to see, or to check, the influence of his writings, he was never condemned as a heretic. Furthermore, Jansen’s writings included statements in which he submits to the Catholic Church.

Based on the writings of Cornelius Otto Jansen, his followers worked to exhibit an incredible level of piety. Furthermore, Jansenists spent time in both intense prayer and confession before receiving Holy Communion. This was in direct opposition to the belief of St. Pius X, who finally condemned Jansenism, that Communion ought to be taken frequently, and as early in life as possible. He believed that children ought to take Communion as soon as they were old enough to distinguish between the Host and common bread. In Jansenism, much like in Calvinism, only a select few of all human beings are destined to be saved.

The convent at Port Royal, which is in Southwest Paris, took to heart much of the Jansenist doctrine. Under the pressure of the Jesuits, however, King Louis XIV razed the convent in 1710 after the last nuns had been removed from the premises. The convent had been in operation since the early 1200's. The remains can still be seen today.