The complete history of J ansenism will probably never be written because to write it would involve the study of a movement that grew and changed constantly for more than two hundred years and found a different expression in many countries, especially France, Holland, and Italy. Of course the ordinary Frenchman of any education would think that he knew something about Jansenism. For him, and for many Englishmen of some French culture, Jansenism is a heresy about grace and predestination that found expression in the Augustinus of Cornelius Janssens or Jansenius, Bishop of Ypres and at one time professor in the university of Louvain. 1 The theological position of J ansenius was adopted by his friend, Jean Duvergier de Hauranne, commonly known as the Abbe de S. Cyran, a director of the monas­ tery of Port Royal des Champs. Through its relations with S. Cyran and with Antoine Arnauld, brother of Angelique Arnauld, Abbess of Port Royal, the monastery entered into the theological controversies of the time, especially after Arnauld's severe moral work - De fa Frl­ quente Communion. 2 But to the ordinary Frenchman, Port Royal, besides its quarrels about predestination, is chiefly memorable for its great literary names, Pascal, Racine, Boileau, and to some extent La Fontaine and Mme de Sevigne. What Jansenism really stood for and what became of its ideal after the brutal demolition of Port Royal in 1709 by Louis XIV is but little known.