But when Agnes Sorel died in agony at the age of 28, rumours began to circulate that she had been murdered.
The lover of Charles VII, Sorel enraged the king’s son and heir, the future Louis XI, with the influence she exerted over his father’s court.
Rumour has it the dauphin paid one of the king’s officials to poison Sorel, who died in 1450 shortly after giving birth. Now French historians hope to clear up what has become one of their country’s most enduring mysteries, by exhuming her body to discover how she died.
Sorel had already given the king three daughters and was eight months pregnant with the fourth when she decided to leave the royal retreat at Loches, in western France, to join her lover in Normandy, where he was fighting the English.
A long and difficult journey over icy and bumpy February roads probably led to her giving birth prematurely upon her arrival in Jumiges to a sickly infant who soon died. Sorel then began suffering agonising stomach pains and died within days.
Officially, her death was attributed to "inflammation of the stomach", but rumours began circulating that she had been poisoned by her friend, Jacques Le Coeur, the king’s immensely wealthy and powerful finance minister.
Le Coeur, so the rumour went, had been ordered to kill Sorel by the dauphin, a notorious manipulator who hated his father’s mistress.
Whether Sorel was poisoned and, if so, whether Le Coeur was responsible, has remained one of the great unsolved mysteries of French history. However, a year after her death, the rumours were strong enough for Charles VII to order the arrest and torture of his trusted financial adviser on suspicion of Sorel’s murder and other crimes.
Le Coeur "confessed" under torture and was condemned to die in 1453. He escaped from prison in Poitiers and took refuge with the pope in Rome. He died in November 1456 on the island of Chio.
Born into lesser nobility in 1422 in the village of Fromenteau in Tourraine, Sorel first met King Charles VII in 1443 when she was a lady-in-waiting to Isabelle de Lorraine, the wife of Ren d’Anjou.
Described as stunted, melancholy, shy and unattractive, Charles needed to pad out his clothing to give him a more imposing stature. The 21-year-old Sorel, with her almond-shaped blue eyes, was already considered a great beauty and the king fell madly in love with her at first sight, with nobles of the time reporting that he was struck dumb after seeing her and could not sleep.
By all accounts, Sorel, who was popularly known as "Beauty of Beauties", succeeded in getting Charles to relax and imbued him with a new-found confidence.
A witty and astute woman, as well as a beautiful one, she was a good judge of character and helped to surround him with solid advisers, so much so, that he went down in history under the title "Charles the Well-Served".
At court, her daring style was much imitated. She plucked her eyebrows and piled her hair on top of her head to enhance her high-domed forehead. She also wore exceedingly low-cut gowns, with perfumed trains up to eight metres long.
The king was besotted with her and heaped extravagant presents upon her and their daughters, each of whom received a chteau at birth.
Charles was weak and vacillating and there is little doubt that he was dominated by Sorel and, even if, after her death, he quickly found comfort in the arms of her cousin, Antoinette de Maignelais, he was a broken man who soon retreated into melancholy and weakness.
Sorel’s influence and power at court made her enemies, the most powerful of which was the king’s son, the dauphin. He is known to have once threatened Sorel with a dagger and some believe that he was behind a plot to murder her.
Now, more than 550 years after her death, historians and scientists will carry out DNA and other tests on Sorel’s remains in an attempt to determine if she was, indeed, poisoned.
"The urn placed inside the tomb and which contains the remains of Agnes Sorel, including her face, skull and mandible bones, will be sent to the Central University Hospital in Lille where DNA testing will be carried out," Pascal Dubrizay, the deputy mayor of Loches, said.
"Following our decision to move the tomb, an archaeologist offered to analyse the remains of the deceased in order to try to establish the exact cause of death and the exact date of her birth."
The national gendarmerie’s Institute of Criminal Research at Rosny-sous-Bois, on the outskirts of Paris, will establish Sorel’s genetic profile and will also recreate a three-dimensional sculpture of her face.
Once the examinations are finished, the tomb, which until now has been placed in the aisle of the royal crypt, will be placed in the Collegiate Church of Saint Ours, next to the chteau, in accordance with Agnes Sorel’s last wishes.