Diane de Poitiers (9 January 1500 – 25 April 1566) was a French noblewoman and courtier who wielded much power and influence as King Henry II's royal mistress and adviser until his death.

[2] When still a girl, Diane was briefly in the retinue of Princess Anne de Beaujeu,[2] King Charles VIII's eldest sister who skillfully held the regency of France during his minority.

Like her fellow charges, Diane was educated according to the principles of Renaissance humanism, including Greek and Latin, rhetoric, etiquette,[2] finance, law, and architecture.

On 29 March 1515, at the age of 15, Diane was married to Louis de Brézé, seigneur d'Anet, Count of Maulévrier, and Grand Seneschal of Normandy, who was 39 years her senior.

She managed to retain her late husband's emoluments as grand seneschal of Normandy and challenged in court the obligation to return the family's appanages to the royal domain.

Impressed, King Francis I allowed the widowed Diane to manage her inherited estates without the supervision of a male guardian and keep their considerable revenues.

The experience may account for the strong impression that Diane made on Henry, as the very embodiment of the ideal gentlewoman: as his mother was already dead, his grandmother's lady-in-waiting gave him the farewell kiss when he was sent to Spain.

[13] As the couple remained childless and she became concerned by rumours of a possible repudiation of a royal wife that she had in control, Diane made sure that Henry's visits to the marital bedroom would be frequent,[14] to the point that he had ten legitimate children.

[16] By then, Diane's position in the Court was such that when Pope Paul III sent the new Queen the "Golden Rose", he also presented the royal mistress with a pearl necklace.

Although she was not openly involved, Diane's sharp intellect, confident maturity and loyalty to Henry II made her his most dependable ally in the court.

One of the most successful royal mistresses in acquiring wealth, Diane used her income to build castles by commissioning architect Philibert de l'Orme.

[19] There is the mortuary chapel built according to Diane's wishes to contain her tomb, commissioned from architect Claude de Foucques by her daughter Louise, Duchess of Aumale.

Although its ownership remained with the crown until 1555, Diane was the unquestioned mistress of Château de Chenonceau, the jewel of the Loire Renaissance palaces.

In 1555, she asked de l'Orme to build the arched bridge joining the château to its opposite bank and oversaw the planting of extensive gardens filled with varieties of fruit trees.