Marie Geneviève Radix de Sainte-Foy
Marie Geneviève Radix de Sainte-Foy (1729–1809), was a French noble, mistress to Louis XV of France as well as to Louis, Dauphin of France (son of Louis XV) in 1750–51. 

She was the daughter of Claude Mathieu Radix, seigneur de Chevillon and Marie Elizabeth Geneviève Denis. She married in 1750 to Jean François Boudrey (1701–1760), and in 1761 to Nicolas Augustin de Malbec de Montjoc, marquis de Briges. 

According to the traditional description of the event, she received an invitation to an assignation from both the king and the dauphin as the same occasion; she showed her husband the invitation, and it was decided that she should accept the invitation of the king. Reportedly she did so for monetary concerns. On a later occasion, however, she also accepted an assignation with the dauphin, and for a time she alternated as the lover of both who, as expressed by René Louis de Voyer de Paulmy d'Argenson, "sailed to Cythera on the same ship". In both cases the relationship was an unofficial one and in no effect was she ever an officially acknowledged mistress to either of them. 

For the king the affair was a temporary one; it took place in at about the same time as the king's affair to Irène du Buisson de Longpré, and she was not regarded a threat to the position of Madame de Pompadour. In the case of the dauphin, the matter was a more uncommon one and the secret affair caused discontent with Maria Josepha of Saxony, Dauphine of France, because it was not usually the habit of the dauphin to have affairs. Maria Josepha, however, reportedly became convinced that the matter was a purely temporary one during her pregnancy and that her spouse would never have an official mistress like his father. The affair did indeed prove to be temporary, and the dauphin would indeed never have an official mistress. 

Not long after this, Louis XV had Marie-Louise O'Murphy installed at the Parc-aux-Cerfs.
Q625369
mistress
Concept
Q7738
Louis XV of France
PER
Q1127464
Louis, Dauphin of France (son of Louis XV)
PER
Q1393507
René Louis de Voyer de Paulmy d'Argenson
PER
Q207239
Cythera
LOC
Q1673324
Irène du Buisson de Longpré
Concept
Q188965
Madame de Pompadour
PER
Q163043
Maria Josepha of Saxony, Dauphine of France
PER
Q234291
Marie-Louise O'Murphy
PER
Q2629756
Parc-aux-Cerfs
UNK
Q90575449
Marie Geneviève Radix de Sainte-Foy
PER
1750-01-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
1750
DATE
1750-01-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
1750
DATE
1761-01-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
1761
DATE
+1729^^http://www.w3.org/2001/XMLSchema#decimal
1729
NUMBER
+1809^^http://www.w3.org/2001/XMLSchema#decimal
1809
NUMBER
+51^^http://www.w3.org/2001/XMLSchema#decimal
51
NUMBER
+1701^^http://www.w3.org/2001/XMLSchema#decimal
1701
NUMBER
+1760^^http://www.w3.org/2001/XMLSchema#decimal
1760
NUMBER
child