Marie Anne de La Trémoille, princesse des Ursins (1642 – 5 December 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 Marie Anne, now widowed, 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.
Till 1714, the year of the death of the queen, she was the most powerful person in the country. Her functions about the king and queen were almost those of a nurse. Her letters show that she had to put them to bed at night, and get them up in the morning. She gives a most amusing description of her embarrassments when she had to enter the royal bedroom, laden with articles of clothing and furniture. But if the Camarera mayor de Palacio did the work of a domestic servant, it was for a serious political purpose. She was expected to look after French interests in the palace, and to manage the Spanish nobles, many of whom were of the Austrian party, and who were generally opposed to foreign ways, or to interferences with the absurdly elaborate etiquette of the Spanish court.
Madame des Ursins was resolved not to be a mere agent of Versailles. During the first period of her tenure of office she was in frequent conflict with the French ambassadors, who claimed the right of sitting in the council and of directing the government. Madame des Ursins wisely held that the young king should rely as much as possible on his Spanish subjects. In 1704 her enemies at the French court secured her recall. But she still had the support of Madame de Maintenon, and her own tact enabled her to placate Louis XIV.
In 1705 she returned to Spain, with a free hand, and with what was practically the power to name her own ministry. During the worst times of the war of the Spanish Succession she was the real head of the Bourbon party, and was well aided by Princess Maria Luisa of Savoy, the spirited young queen of Philip V. She did not hesitate to quarrel even with such powerful personages as the Cardinal Archbishop of Toledo, Portocarrero, when they proved hostile, but she was so far from offending the pride of the nation, that when in 1709 Louis the XIV, severely pressed by the allies, threatened, or pretended, to desert the cause of his grandson, she dismissed all Frenchmen from the court and threw the king on the support of the Castilians.
Her influence on the sovereigns was so strong that it would probably have lasted all through her life, but for the death of the queen. Madame des Ursins confesses in her voluminous correspondence that she made herself a burden to the king in her anxiety to exclude him from all other influence. She certainly rendered him ridiculous by watching him as if he were a child. Philip was too weak to break the yoke himself, and could insist only that he should be supplied with a wife. Madame des Ursins was persuaded by Alberoni to arrange a marriage with Elisabeth of Parma, hoping to govern the new queen as she had done the old.
However, Saint-Simon related that the princess tried first to become queen of Spain herself and, when this plan failed, she persuaded Alberoni to choose Elisabeth Farnese of Parma, hoping that Elisabeth, who could not have hoped for a royal crown, would be indebted to her. In trying to become queen, Mme des Ursins lost the last remnants of support from Mme de Maintenon; in promoting Elisabeth without French consent, she also lost Louis XIV's support.
Elisabeth had, however, stipulated that she should be allowed to dismiss the Camarera Mayor. Madame des Ursins, who had gone to meet the new queen at Quadraque near the frontier, was driven from her presence with insult, and sent out of Spain without being allowed to change her court dress, in such bitter weather that the coachman lost his hand by frostbite. In Bayonne, she waited for a while hoping that the King would call her back, in vain. Saint-Simon believes that the dismissal had been schemed beforehand, and even happened with consent of the king. After a short stay in France, she went to Italy, and finally established herself in Rome, where she imposed her personality on the small English emigre Jacobite court of "The Old Pretender", effectively running it until she died on 5 December 1722. She had the final satisfaction of meeting Alberoni there after his fall.
Saint-Simon, in his Mémoires, draws a devastating portrait of a scheming intrigant, and her accomplices and minion, rather unjustly, and without crediting the important and positive role the princess played in getting and keeping the royal pair on the throne, and arranging the poor finances of the kingdom of Spain.( Despite his harsh view of her political influence, Saint-Simon admits that he personally liked and admired her.) A readable life of Madame des Ursins was published in Paris in 1858 by NF Combes, and there is an English life by C Hill, The Princess des Ursins in Spain (London, 1899). See her Lettres inédites, edited by A Geoffroy (Paris, 1859), and her correspondence with Madame de Maintenon (Paris, 1826).
Madame des Ursins also is credited as having introduced the essence of bitter orange tree as a fashionable fragrance by using it to perfume her gloves and her bath. Since then, the name of Neroli (she was princess of Nerola, in Lazio, Italy) has been used to describe this essence. Neroli has a refreshing and distinctive, spicy aroma with sweet and flowery notes.