Blanche of Castile was born in 1188, in Palencia, Castile. She was the third daughter of Eleanor of England, daughter of King Henry II of England, and King Alfonso VIII of Castile. In 1200, King John of England made a treaty with King Philip of France, which said that a daughter of John’s sister, Eleanor of England would marry Philip’s son, Louis. John’s mother, Eleanor of Aquitaine, was sent to Castile to judge which of Blanche and her sisters was most suitable for the role of queen-consort of France. Eleanor had been queen-consort of France herself at one point, so she knew what it took to fill the role.

Eleanor of Aquitaine judged that while Blanche’s older sister, Urraca, was certainly more beautiful, it was Blanche that was better suited to be a queen. Blanche, who was just twelve, was married to Dauphin Louis, who was just thirteen. Their marriage would not be consummated for some time, but it soon was, as their first daughter, Blanche, was born five years after the marriage.

Blanche and Louis had thirteen children, though only five survived to adulthood. Louis IX would become King of France, Robert of Artois would be killed in battle, Alphonse became Count of Poitou, Auvergne, and Toulouse, the only daughter Isabelle devoted her life to God and never married, and would eventually be canonized as a saint with her feast day on February 22nd, and Charles, Count of Anjou, Maine, Forcalquier, and King of Sicily. She raised her children to be extremely pious, and two became saints. Blanche also owned many books and used those to educate her children well.

When the Barons rebelled against King John over in England, they invited Louis—who was still waiting around for his turn to be King of France—to come and take over the country. He was chosen since Blanche was King John’s niece and so Louis and Blanche’s children would have a claim to the English throne. Louis and Blanche weren’t ones to turn down becoming monarchs, so they marched over to England and defeated King John.

It wasn’t as easy as they thought, however, and not many supported King Louis I of England, not even his father. Blanche was his sole supporter, and she was a powerful ally to have. She helped him hold out for as long as he could, but the French forces were eventually crushed by King John’s, and Louis and Blanche were sent packing after having been given a large sum of money in exchange for agreeing that they had never been King and Queen of England.

Louis’s father died in 1223, leaving the throne to him and Blanche. The couple was crowned in August of that year. After a short few years on a secure throne, Louis died of dysentery in 1226, leaving his thirty-eight-year-old wife as regent for their son, twelve-year-old Louis IX. Blanche quickly had him crowned and had the reluctant barons swear loyalty to her son, but their situation was precarious as the old king had died without completely subduing the southern nobles. Blanche pulled together an army and marched south with her men, keeping the nobles under their thumb.

Henry III of England, Blanche’s cousin, was one of her main enemies. He already had vast holdings in France inherited from his grandparents, the Duke of Normandy and Duchess of Aquitaine, and he was looking to take more. When Henry invaded, Brittany rebelled, but the whole thing was quickly put down by the King and Queen Regent.

Blanche’s son was married to Margaret of Provence in 1234, whose sister later became Queen of England by marriage to Henry III. Margaret’s other two sisters, Sanchia and Beatrice, became Queens of Germany and Sicily respectively. Blanche’s son began ruling on his own around this time, but Blanche continued to advise him and be a powerful force in the country. She hated that more attention was being paid to her daughter-in-law than to her, so she made it her mission to drive a wedge between her previously happy son and his wife.

Blanche served as regent once more when all four of her sons marched off to Crusade. The king would be captured and his younger brother would be killed in Egypt. Blanche died in 1252 when the king was still on Crusade, aged sixty-four. Her son was so devastated when he heard of her death the following spring that he reportedly didn’t speak to anyone for two days. The Queen was buried in Maubuisson Abbey, which she had founded.