It is estimated that Agnès was born in 1422 in Touraine, France. Her family was part of the provincial nobility. From a young age, Agnès worked in the service of Isabelle of Lorraine and her husband René of Anjou, who was the brother-in- law of King Charles VII of France. From 1444, Agnès became Lady in waiting to the Queen, Marie of Anjou. It is unknown how Agnès and the King came to be romantically involved, but it was before 1443, as the King had publically proclaimed that he was going to abandon his pregnant wife Marie for Agnès by April that year. In order for Agnès to be able to live at court or at least visit as much as she liked, she needed to have a court position, so the Queen would have to endure her husband’s mistress being in her service. Around this time, Charles gave Agnès the beautiful Chateau of Beauté, one of the finest properties in the whole region and the reason she is often referred to as the Dame de Beauté.
Mistresses were not a new feature in France, but Agnès is known for transforming the role of mistress into a semi-official role, the Maîtresse-en -titre. In 1444, a child named Marie was born to the King and his mistress. After her birth, the King proclaimed that Agnès was now his official mistress. This had never been done before. The new Maîtresse was provided with endless gifts by the King, properties, exotic fabrics, tapestries, and jewels. Agnès used her newfound wealth to dress herself in a way which would show that she was above the rest of the ladies at court and even above the Queen in the King’s eyes. Her collection of jewellery was worth staggering amounts of money and included exquisite gold necklaces and what is said to be the very first cut diamond. Non-Royal women were not permitted to wear diamonds, so Agnès made a bold statement by doing so. This soon sparked a love for diamond jewellery with royalty and noblewomen; Mary of Burgundy received the very first diamond engagement ring three decades later. Aside from her fine clothes and jewellery, Agnès also started what seems now as a rather odd trend; she began to wear very low cut dresses or sometimes left the bodice of her dress unlaced so that her breasts were fully exposed.
Agnès is not just remembered as a court trendsetter; she was also a deeply religious woman who gave generously to the charities she supported. Agnès was open about her relationship with the King and did not live her life racked with guilt over her sins as a mistress; she was even given a Papal Absolution, which forgave her wrongdoings. King Charles was transformed with Agnès on his arm, his depression apparently disappeared, and he was suddenly a much more capable king. The finances of the state, the justice system and the administration of the government all underwent huge changes during this time. Although there is no proof, it is hard to believe that Agnès, who was a highly intelligent woman, had no part to play in these changes. Agnès used her charms and her wit to keep courtiers and nobles on the King’s side, and court factions began to develop around her and follow her orders far more than those of the Queen. This element of political control became a feature for the French Maîtresse over the coming centuries, with women such as Diane de Poitiers and Madame de Pompadour helping to run the country behind the scenes.
Between 1444 and 1450, Agnès gave birth to three daughters; Marie, Jeanne and Charlotte. Her final pregnancy ended in a stillbirth. Agnès had been travelling to visit the King, who was away on a campaign when she went into labour. Unfortunately, she and the child both died on 9 February 1450. At the time, it was said that Agnès had contracted dysentery, but the King suspected she had been poisoned by the minister Jacques Coeur or the Dauphin Louis, who had always opposed their union. Agnès died at the age of 28, leaving King Charles distraught. She was made a Duchess after death so that she could be provided with the most magnificent of funerals.
In 2005, the mystery surrounding Agnès’ death was finally cleared up; her body was exhumed, and her remains were tested to determine the cause of her death. While it cannot be completely confirmed, Philippe Charlier, a forensic scientist, has said that it is more than likely that the mistress had been poisoned over time with mercury as high levels were found in her body, mercury was also a cure for parasites, but the levels in her body indicate poisoning.1