Marie de Ploeuc de Tymeur

Louise was the daughter of Guillaume de Penancoët, Seigneur de Kérouaille (d. 1690) and his wife (married on 27 February 1645) Marie de Ploeuc de Timeur (d. January 1709),

[1] paternal granddaughter of René de Penancoët, Seigneur de Kérouaille et Villeneuve, and his wife (married on 12 October 1602) Julienne Emery du Pont-l'Abbé, Dame du Chef du Bois,

and maternal granddaughter of Sébastien de Ploeuc, Marquis de Timeur, and his wife (married on 8 January 1617) Marie de Rieux (d. 1628).

The name Kérouaille was derived from an heiress whom an ancestor François de Penhoët had married in 1330.