Origin of Jansenism
In Jansenist thought, human beings were born sinful, and without divine help a human being could never become good. This led the Jansenists to seek to exhibit a high level of piety and moral rectitude, and to prepare carefully through prayer and confession before receiving Communion (hence Jansenists favored less frequent reception). The Jansenist idea of predestination, based on Augustine's writing and close to that of Calvinism, was that only a portion of human beings, the "elect," were destined to be saved. Unlike Calvinism, however, Jansenism lacked a doctrine of assurance, deeming salvation unknowable even to the saved.
Jansenist theology
Jansenism was condemned as heretical in several papal bulls, notably by Pope Innocent X, Alexander VII (Ad Sanctam Beati Petri Sedem; Catholic Encyclopedia article) and Clement XI (Unigenitus). Because Jansen himself died before his work was published, and he included statements of submission to the Catholic Church in it, he himself was never formally considered a heretic. The final condemnation of Jansenism was by St. Pius X, who, in contrast to Jansenist reticence over communion, advocated daily communion for Catholics, and communion for children as soon as they could distinguish the sacred Host from ordinary bread. Jansenism was officially outlawed by the Catholic Church in 1712.
In France, King Louis XIV, acting under the pressures of the Jesuits, sought the end of Jansenism. Particularly targeted was the convent of Port-Royal. In a highly symbolic gesture, the convent was razed in 1710 after the last nuns had been forcibly removed.
Papal condemnation
Acceptants were those members of the Jansenism branch of Catholicism who accepted the bull Unigenitus, which opened the final phase of the Jansenist controversy in France and condemned 101 propositions of the French Jansenist theologian Pasquier Quesnel.
Later Developments
Baianism
Dale K. Van Kley