Jean Alespée, Ad Ensem, born in 1357, the son of Pierre Alespée, was licentiate in civil law, and bachelor of canon law at Paris, and canon of Rouen from 1412.

He was treasurer of the diocese under Archbishop Louis d'Harcourt (1412-1413), vicar-general of that prelate, with his intimate friend Nicolas de Venderès (1415-1422), and was allied with the English party.
By letter of nomination of Henry V he was concurrently canon of Evreux, Bayeux, of the collegiate church of Andely, and curé of Hautot le Vatois.

He died at Rouen, at the home of Jean Marcel, on August 16, 1434, in his seventy-seventh year, after having been ill for some time at the home of Pierre Miget, prior of Longueville. Jean Alespée was a rich man and a lover of fine books. His confrères put him in charge, in 1424, Of supervising the construction of the library of the cathedral. Jean Alespée was related to the Estouteville and Mallet de Graville families. He was also a friend of Nicolas de Venderès who made an inventory of his possessions.

Jean Alespée, appears especially to have been a timid man; he always took refuge behind the opinions of his teachers and lords, the theologians.

Jean Riquier, witness at the Rehabilitation, reported that Alespée wept freely at the burning of Jeanne and that he said publicly: "I wish that my soul were where I believe the soul of this girt is."