Marie Anne de La Trémoille, princesse des Ursins (1642 – December 5, 1722), was a French courtier and royal favourite known for her political influence, being a de facto ruler of Spain from 1701 until 1714. She spent most of her life as an agent of French influence abroad, at first in Rome, and then in Spain under the new Bourbon dynasty, followed by a final period at the exiled Stuart court in Rome. She played a central role at the Spanish royal court during the first years of the reign of Philip V before her ousting from the country following a power struggle with Elisabeth of Parma.
She was the daughter of the duc de Noirmoutier and his wife Renée Julie Aubery de Tilleport. She was married young to Adrien Blaise de Talleyrand, prince de Chalais. Her husband, having been concerned in the duel of four against four, in which the duke of Beauvilliers was killed in 1663, was compelled to flee France. He died soon afterward in Spain, and his widow established herself in Rome. In 1675 she married Flavio Orsini, duke of Bracciano. The marriage was far from harmonious, but her husband left her his fortune (popular imagination thought it to be huge, in reality, the duke was almost bankrupt) and the leadership of the French party in Rome. It brought her a series of lawsuits and troubles with Livio Odescalchi, nephew of Pope Innocent XI, who claimed that he had been adopted by the duke. At last the widow sold the title and estates to Odescalchi.
She then assumed the title of Princesse des Ursins, a corruption of Orsini, and was tacitly allowed to use it, though it had no legal existence. The Princesse des Ursins had indulged in a great deal of unofficial diplomacy at Rome, more particularly with Neapolitans and Spaniards of rank, whom it was desirable to secure as French partisans in view of the approaching death of Charles II of Spain, and the plans of Louis XIV for placing his family on the Spanish throne.
Her services in favour of France were rewarded in 1699 by a pension which her problematic financial situation made necessary to her. When Philip de France, duc d'Anjou, grandson of the French king, was declared heir by the will of Charles II, the princess took an active part in arranging his marriage with Princess Maria Luisa of Savoy, a daughter of the duke of Savoy. Her ambition was to secure the post of Camarera mayor de Palacio, or chief of the household to the young queen, a child of barely thirteen. By quiet diplomacy, and the help of Madame de Maintenon, she succeeded, and in 1701 she accompanied the young queen to Spain.