Who was Diane de Poitiers, and how did she affect Catherine de’ Medici’s marriage to Henry II?

Diane de Poitiers was a noblewoman and the long-term mistress of Henry II of France, who was 20 years her junior.1

Her presence significantly impacted Catherine de’ Medici’s experience as queen. Throughout Henry II’s reign, Diane held court with the influence of a queen in all but name, while Catherine was relegated to a life of comparative obscurity. Despite Henry’s deep and abiding attachment to Diane, Catherine’s marriage remained functional; she bore him 10 children and eventually served as regent during the king's absences.12

Following Henry II’s death in 1559, the power dynamic shifted. Catherine asserted her authority by forcing Diane to return crown jewels that the king had gifted her and compelling her to exchange the château of Chenonceaux for the fortress-like château of Chaumont.1