Denis Gastinel, licentiate in canon law at Paris in 1418, had studied under another of Jeanne's judges, Nicolas Le Roux, Abbot of La Croix Saint Leufroy.

He was present in 1419 at the oath of allegiance made by the abbot of Jumièges to King Henry VI. He was provided with numerous benefices by the conquering king; he became curé of Troismonts in 1420, canon of Nôtre Dame de la Ronde in 1421, and canon of the cathedral of Rouen in 1422. He was dean of Andely in 1423, curé of Neville by favor of an English knight, Walter Hungerford, in 1427, and was vicar-general during the vacancy of the archiepiscopal see. He took part in the Estates convoked by Bedford at Lisieux in 1436.

He died on December 13, 1440, leaving among the executors of his will his friend Jean Caval.

He was a man entirely devoted to the English in the Chapter of Rouen, which he remembered in his will. Bedford recompensed him for his zeal by naming him, in 1424, a member of the royal council, with a salary of a hundred livres a year. His judgment in the matter of the Maid was very vigorous; at the time of the definitive sentence, he displayed the same spirit and screened himself behind the opinion of the Abbot of Fécamp, Gilles de Duremort.