Maîtresse-en-titre
The maîtresse-en-titre (French: [mɛtʁɛs ɑ̃ titʁ]) was the chief mistress of the king of France. It was a semi-official position which came with its own apartments. The title came into use during the reign of Henry IV and continued until the reign of Louis XV.
From the reign of Louis XIV, the term has been applied, both in translation ("official mistress") and in the original French, to refer to the main mistress of any monarch or prominent man when his relationship with her is not clandestine, e.g. Vibeke Kruse, Jeanne Baptiste d'Albert de Luynes, Lola Montez, Magda Lupescu.
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