Men have had mistresses since the beginning of time. However, Agnes Sorel was the first one to parlay that into a position.
She was the acknowledged mistress of the French king, the first woman to hold that semi-official position which was to be of so great importance in the subsequent history of the old regime. Agnes met the king in and Charles was smitten.
Legend has it she wore a creation of uncut diamonds by Jacques Coeur to draw attention to her decolletage inventing the diamond necklace. Charles showered her with money, land and jewels cut and set by the wealthy Jacques Coeur. Agnes, in turn, helped Charles finance his endless wars against the English. One such financier was Jacques Coeur, whom she had thrown so much business to.
Along with diamonds, Agnes set other fashion trends at the French court. She was known for wearing very low cut gowns, so low in fact that one or both of her breasts were exposed.
This was scandalous but set a trend. Her bosom was so magnificent she served as a model for Jean Fourquet in a portrait of the Virgin Mary.
The Virgin and the Child surrounded by angels features the Virgin offering her breast to the Christ Child. The great influence Agnes had on the king as well as her outrageous tastes earned her many enemies at court. It is not surprising that her sudden death in was treated as suspicious.