Question: Who is the maternal grandmother of Henri, Duke Of Verneuil?
Sentence (from "Henri, Duke of Verneuil"): Gaston Henri de Bourbon, Duke of Verneuil (3 November 1601 – 28 May 1682), was the illegitimate son of King Henry IV of France and his mistress, Catherine Henriette de Balzac d'Entragues.
Relevant evidence: Yes