René-Prosper Tassin

Who was René-Prosper Tassin?

René-Prosper Tassin was a French historian, belonging to the Benedictine Congregation of Saint-Maur.

Tassin was born at Lonlay, in the Diocese of Le Mans. He was professed at the Abbey of Jumièges in 1718. United in close friendship with his brother in religion, Dom Charles-François Toustain, he collaborated with him on a new edition of the works of Theodore the Studite, which task led them to visit Rome together. Their work was interrupted by a dispute between the Benedictine Abbey of St. Ouen and the chapter of Rouen, which was supported by the erudite Jean Saas. Tassin and his friend wrote against Saas in defence of their brethren.

They then resided at the Abbey of Rouen where they remained till 1747, when they were summoned to the Abbey of Saint-Germain-des-Prés, at Paris, by their general. To defend the authenticity of the deeds of their abbey they were obliged to make a deep study of diplomatics, dealing with diplomas, charters, and other official documents, for which Jean Mabillon had laid the foundations in his great Latin work, De re diplomatica.