[4] Her mother, Marie of Champagne, decided to join him shortly after his departure, leaving their daughters Joan and Margaret in the care of their paternal uncle, Philip I of Namur.

He gave his future father-in-law custody of Joan and Margaret, who were raised in Paris alongside the young Count Theobald IV of Champagne.

Joan and Ferdinand only could obtain their release after signing the Treaty of Pont-à-Vendin (25 February 1212), under which they were forced to surrender the towns of Aire-sur-la-Lys and Saint-Omer to France, recognizing the previous occupation of Prince Louis over those lands.

[6] After this event, Joan and Ferdinand decided to join in an alliance with the former allies of Baldwin IX, King John of England and Otto IV, Holy Roman Emperor.

In 1221, she sought to marry Peter Mauclerc (Duke-Regent of Brittany and widower of Alix of Thouars) but King Philip II refused.

The French King, viewing this union with suspicion, informed Pope Innocent III that Bouchard before his wedding had already taken holy orders as sub-deacon.

[4] The next conflict to shake Joan's rule took place in 1224, when she wanted to acquire, through her advisor Arnoul of Audernarde, the castellany of Bruges, which King Philip II had entrusted to John of Nesle, bailiff of Flanders, after the Battle of Bouvines.

Joan then appealed to the new King Louis VIII of France at a meeting in his court at Melun, contending that, due to her rank, she could only be judged by her peers.

[10] The Chronique rimée of Philippe Mouskes reported at the same time that a mysterious stranger distributed large sums of money announcing the return of Baldwin.

[4][10] Before launching military operations, Louis VIII sent his aunt Sybille of Hainaut, Dowager Lady of Beaujeu and sister of Baldwin IX, to meet the hermit.

[4] It is likely that Bouchard of Avesnes, the former husband of Margaret, was behind the plot:[10] the false Baldwin IX had recognized the legitimate rights of his eldest son as heir of Flanders and Hainaut.

[citation needed] Whether as a ploy or out of genuine willingness to turn the page, Joan intensified her efforts to marry Peter Mauclerc, the widowed duke and regent of Brittany.

However, King Louis VIII refused the consent to a marriage between Mauclerc and the Countess, fearing that the royal demesne, squeezed between their domains, would be too endangered.

To finally end Joan's marital pretensions, the French King obtained from the Pope the renewal of her marriage with Ferdinand, while forcing her to a treaty and a ransom for her imprisoned husband.

[12] In April 1226, the Treaty of Melun was signed between Joan and Louis VIII, under which Ferdinand's ransom was fixed at 50,000 livres parisis payable in two installments.

The Treaty also stipulated that the cities of Lille, Douai and Lécluse would be surrendered to France as a pledge until full payment of this considerable amount was made.

After the death of her husband, Joan wanted to marry Simon de Montfort, 6th Earl of Leicester, but since he was still loyal to the English crown at this point, this did not sit well with Louis IX, who refused to give his consent.

[4] After Ferdinand's death, the couple's daughter and heir presumptive, Marie of Portugal, was sent to Paris to be educated there, following Louis IX's demands.

Following Blanche of Castile's suggestion, Joan agreed to marry Thomas of Savoy, Count of Maurienne and Lord of Piedmont, maternal uncle of Margaret of Provence, wife of Louis IX.

[4] Joan died on 5 December 1244 at the Abbey of Marquette near Lille, where she had retired shortly before as a nun,[18] and was buried next to her first husband in the mausoleum that she had previously built for him.

[7] After the return of her husband Ferdinand, she confirmed this political orientation, by granting Douai, Ghent, Ypres, Bruges and Lederzeele new privileges, which gave them greater autonomy vis-à-vis from the Comital power.

Then, after her marriage with Thomas of Savoy (1237–1244), she complemented this policy through tax exemptions, reorganization of the judicial system, measures to promote river commerce and sea ports, concerning the cities of Bergues, Bourbourg, Bruges, Damme, Veurne, Muiden and Kaprijke.

Under constant pressure from the Flemish bourgeoisie, aware of Joan's need of their support against the King of France, she pursued a policy that promoted economic development and urban autonomy, not without tax counterparties.

[25] The Countess also promoted and established several monasteries, abbeys and Béguinages in her domains:[2] the most notable of them were located in Mons and Valenciennes (in Hainaut), Bruges, Ghent and Ypres (in Flanders), all founded between 1236 and 1244.

[25] In February 1237, she founded the Hospice Comtesse, for which she donated the gardens of her residence in the castrum of Lille at the site of the old donjon which was destroyed by the French in 1213.

Despite his character hagiographic, this text appears to have been designed both as a book for the instruction and edification of his teenage dedicatee, but also as a wonderful story, near the chivalric romance, including the episode of the Tarasque.

[30] Later medieval chroniclers, such as Matthew Paris, are generally hostile to her; almost all consider that the hermit was indeed the true Baldwin IX of Flanders and by killing him, she committed parricide.

[10] In 1823 Sismondi repeats this thesis of parricide in his Histoire des Français, like the playwrights Fontan and Victor Herbin in their play Jeanne de Flandre in 1835.

[10] The Museum of the Hospice Comtesse has two tapestries of Guillaume Werniers, after drawings of Arnould de Vuez representing Countess Joan.

[36] In the same museum, an anonymous painting of 1632, called "Foundation of the Notre-Dame Hospital", shows Countesses Joan and Margaret, surrounded by the Virgin, St. Augustine and St. Elizabeth of Hungary, as well as monks and nuns of the Hospice Comtesse.