The names of Gunnora de Crepon's parents are unknown, but Robert of Torigni wrote that her father was a forester from the Pays de Caux and according to Dudo of Saint-Quentin she was of noble Danish origin.
Gunnora was probably born c. 950. Her family held sway in western Normandy and Gunnora herself was said to be very wealthy. Her marriage to Richard I was of great political importance, both to her husband and her progeny. Her brother, Herfast de Crepon, was progenitor of a great Norman family.Her sisters and nieces married some of the most important nobles in Normandy.
Richard I, 3rd Duke of Normandy (943-996), reigned fifty-five years. Richard either introduced feudalism into Normandy or he greatly expanded it. By the end of his reign, most important Norman landholders held their lands in feudal tenure.
He married (1) Emma, daughter of Hugh Magnus, the Great, Count of Paris, no issue; (2) Lady Gonnor de Crepon (Gummora) of Denmark.