Her Wikipedia article begins, "Charlotte de Beaune Semblançay, Viscountess of Tours, Baroness de Sauve, Marquise de Noirmoutier (26 October 1551 – 30 September 1617) was a French noblewoman and a mistress of King Henry of Navarre, who later ruled as King Henry IV of France. She was a member of Queen Mother Catherine de' Medici's notorious "Flying Squadron" (L'escadron volant in French), a group of beautiful female spies and informants recruited to seduce important men at Court, and thereby extract information to pass on to the Queen Mother...”
From Wikimedia. The image was full of cracked paint borders that I removed with Photoshop. The dark background, except for the signature block at the upper right corner, were blurred with Photoshop.