Marguerite des Marguerites
[the pearl of pearls ]. So Francois called his sister (Marguerite de Valois), authoress of the Heptameron. She married twice: first, the Duc d'Alencon, and then Henri d'Albret, king of Navarre, and was the mother of Henry IV. of France. Henri [IV.] married a Marguerite, but this Marguerite was the daughter of Henri II. and Catherine de Medicis. The former befriended the Huguenots, the latter was a rigid Catholic, like her mother.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894