Joan of Ponthieu, Dame of Epernon

She acted as regent for her infant granddaughter Jeanne, suo jure Countess of Vendôme from 1371 until the child's premature death in 1372.

Joan was born in France sometime before 1336, the youngest daughter of Jean II de Ponthieu, Count of Aumale (died 1343), and Catherine d'Artois (1296 – November 1368).

She had an elder sister, Blanche de Ponthieu (before 1326 – 12 April/May 1387) who became suo jure Countess of Aumale on 16 January 1340 upon the death of their father.

The seigneury of Épernon was part of her father's inheritance which came into his family about 1256 upon the marriage of his grandmother Laure de Montfort, Dame d'Épernon to the Infante Ferdinand of Castile, Count of Aumale.

In 1362, the castle and town of Vendôme were plundered by the Anglo-Gascon troops of Captain Robert Marcault, and Joan was taken prisoner.