Louis Ellies du Pin, or Dupin (17 June 1657 – 6 June 1719) was a French ecclesiastical historian, who was responsible for the Nouvelle bibliothèque des auteurs ecclésiastiques
Dupin was born at Paris, coming from a noble family of Normandy. His mother, a Vitart, was the niece of Marie des Moulins, grandmother of the poet Jean Racine. When ten years old he entered the college of Harcourt, where he graduated M.A. in 1672. At the age of twenty Dupin accompanied Racine, who made a visit to Nicole for the purpose of becoming reconciled to the gentlemen of Port Royal. But, while not hostile to the Jansenists, Dupin's intellectual attraction was in another direction; he was the disciple of Jean Launoy, a learned critic and a Gallican. He became a pupil of the Sorbonne, and received the degree of B.D. in 1680 and that of D.D. in 1684.
About 1684 Dupin conceived the idea of his Nouvelle bibliothèque des auteurs ecclésiastiques , the first volume of which appeared in 1686. In it he treated simultaneously biography, literary criticism, and the history of dogma; in this he was a pioneer leaving far behind him all previous efforts, Catholic or Protestant, which were still under the influence of the Scholastic method. He was also the first to publish such a collection in a modern language. Unfortunately he was young and worked rapidly. In this way errors crept into his writings and his productions were violently attacked.
Mathieu Petit-Didier, a Benedictine monk, published an anonymous volume of Remarques sur la bibliothèque des auteurs ecclésiastiques de M. Du Pin (Paris, 1691), and this was followed by two other volumes to which the author's name was appended (Paris, 1692 and 1696). Dupin answered him in his fifth volume and Petit-Didier responded in the opening part of his second volume of Remarques. Petit-Didier's observations often seem inspired by prejudices of his time. Thus Dupin had placed St. Macarius the Egyptian in the 4th century, to which indeed he rightly belongs. Having discovered Semipelagianism in this author's works, Petit-Didier concluded that Macarius should come after Pelagius and St. Augustine (II, 198). In reality similar ideas had been professed by many before St. Augustine's time.