Marie Anne de La Trémoille, princesse des Ursins, 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 in the Spanish royal court during the first years of the reign of Philip V, until she was ousted from the country following a power struggle with the new queen consort, Elisabeth Farnese.

A favourite was the intimate companion of a ruler or other important person. In post-classical and early-modern Europe, among other times and places, the term was used of individuals delegated significant political power by a ruler. It was especially a phenomenon of the 16th and 17th centuries, when government had become too complex for many hereditary rulers with no great interest in or talent for it, and political institutions were still evolving. From 1600 to 1660 there were particular successions of all-powerful minister-favourites in much of Europe, particularly in Spain, England, France and Sweden.