Career
During his religious career he was a scholar who was relied upon during the Second Vatican Council. He was known for his books on Christian spirituality and its history. He was chosen by the pope to be part of a team to initiate the International Theological Commission in 1969.
He was ordained a Lutheran minister in 1936 and served as vicar of the Lutheran parish of the Trinity in Paris until World World War World War II He was a professor at the Catholic Institute of Paris until 1963 and then taught in England, Spain, and the United States.
In 1999 he received the Cardinal-Grente prize of the French Academy for all his work. He died 22 October 2004 in Paris, a victim of many years of Alzheimer"son
He was buried in the cemetery of the Abbey of Saint-Wandrille.