In the years 1415 and 1417, the two oldest surviving sons of Charles VI of France died in quick succession: first
Louis, then
Jean. Both brothers had been in the care of the Duke of Burgundy. Yolande was the protectress of her son-in-law, Charles, who became the new Dauphin. She refused Queen Isabeau's orders to return Charles to the French Court; according to Jehan de Bourdigné, when asked she replied, "We have not nurtured and cherished this one for you to make him die like his brothers or to go mad like his father, or to become English like you. I keep him for my own. Come and take him away, if you dare." On 29 April 1417, Louis II of Anjou died of illness, leaving Yolande, at age 33, in control of the House of Anjou. She acted as regent for her son because of his youth. She also had the fate of the French royal house of Valois in her hands. Her young son-in-law, the Dauphin Charles, was exceptionally vulnerable to the designs of the English King,
Henry V, and to his older cousin, John the Fearless, the Duke of Burgundy. Charles' nearest older relatives, the Dukes of Orléans and of Bourbon, had been made prisoners at the Battle of Agincourt and were held captive by the English. With his mother, Queen Isabeau, and the Duke of Burgundy allied with the English, Charles had no resources to support him other than those of the House of Anjou and the smaller House of Armagnac. Following the assassination of John the Fearless at
Montereau in 1419, his son
Philip the Good succeeded him as Duke of Burgundy. With
Henry V of England, Philip forced the
Treaty of Troyes (21 May 1420) on the mentally-ill King Charles VI. The treaty designated Henry as "Regent of France" and heir to the French throne. Following this, the Dauphin Charles was declared disinherited in 1421. When both Henry V of England and Charles VI of France died in 1422 (on 31 August and 21 October, respectively), the Dauphin Charles, at age 19, legitimately became Charles VII of France. Charles' title was challenged by the English and their Burgundian allies, who supported the candidacy of
Henry VI of England, the infant son of Henry V and
Catherine of Valois, Charles' own sister, as king of France. This set the stage for the last phase of the Hundred Years' War: the "War of Charles VII". In this struggle, Yolande played a prominent role in surrounding the young Valois king with advisers and servants associated with the House of Anjou. She manoeuvred
John VI, Duke of Brittany, into breaking an alliance with the English, and was responsible for a soldier from the Breton ducal family,
Arthur de Richemont, becoming
Constable of France in 1425. Using the Constable de Richemont, Yolande was behind the forceful removal of several of Charles VII's advisers. Thus,
La Trémoille was attacked and forced from the court in 1433. The contemporary chronicler
Jean Juvenal des Ursins (1433–44),
Bishop of Beauvais, described Yolande as "the prettiest woman in the kingdom." Bourdigné, chronicler of the house of Anjou, says of her: "She who was said to be the wisest and most beautiful princess in Christendom." Later, King
Louis XI of France recalled that his grandmother had "a man's heart in a woman's body." A twentieth-century French author,
Jehanne d'Orliac, wrote one of the few works specifically on Yolande, and noted that the duchess remains unappreciated for her genius and influence in the reign of Charles VII. "She is mentioned in passing because she is the pivot of all important events for forty-two years in France", while "Joan [of Arc] was in the public eye only eleven months." Yolande retired to Angers and then to Saumur. She continued to play a role in politics. When the bishopric in Angers fell vacant, she threatened Charles VII's candidate with beheading if he showed up in the city. The king backed down and the post went to her secretary. At least from 1439 onwards, her granddaughter
Margaret of Anjou came to live with her. Yolande taught her not only etiquette and literature, but also how to check account books. Her last act before her death was to prepare Margaret for a possible marriage with
Frederick III, Holy Roman Emperor. She received his ambassadors in Samur and presented her granddaughter to them. She died at the town house of the Seigneur de Tucé in
Saumur on 14 November 1442. ==Marriage and issue==