 But his fame does not rest solely on the devotional writings.He was a deep student of antiquity, and so successful in treating of the use of the Psalter in the Christian Church ("De Divinâ Psalmodiâ", Paris, 1663) that Cardinal Pallavicini urged him to undertake the history of the Mass.Realizing the magnitude of the task, he at first declined, but finally set to work and after more than seven years' labour brought out his famous work