Eleanor, named after her mother, was the sixth child of King Henry II and Eleanor of Aquitaine. She was born in about 1161 but in 1170 she was married to Alfonso VIII of Castile. The aim was to secure the border with Aquitaine. One of Eleanor’s daughters born in 1188 was named Blanche. Initially a sister of Blanche’s was betrothed to Philip II of France’s heir but the girls’ grandmother, Eleanor of Aquitaine, decided that it was Blanche who would make a better queen of France.

In 1200, Blanche was escorted across the Pyrenees by her indomitable grandmother, the marriage being made to the benefit of King John of England and involving the dower of lordships held by the English Crown. There was only a year between the bride and groom.

In 1215, King John’s revolting barons offered the English throne to Louis because he was married to Henry II’s granddaughter – and who was going to turn down an entire realm? At one point two thirds of England’s barons recognised Louis as their king, he held London and one third of the country. In 1217 the tide turned in the aftermath of the Battle of Lincoln but Louis tried to regain the military imperative. It was Blanche who put the fleet together that would resupply her husband when Philip II of France refused to help. She gained cash from her father-in-law by threatening to offer her children as hostages. It was all to no avail. Following the Battle of Sandwich in the summer of 1217 Louis was forced to come to terms with King Henry III’s supporters and take himself home.

Philip died in 1223 but was followed three years later by Blanche’s husband. Louis IX was only 12 years old but unlike Henry III’s mother, Blanche had no intention of deserting her son and besides which Louis VIII left the regency in Blanche’s hands on his deathbed. She forced the French magnates to accept the young king and in the capacity of regent played both the military and diplomatic cards in a way that her grandmother would have applauded. In 1229 she forged the Treaty of Paris. She remained an influential political player throughout her life and in 1248 became regent of France for a second time when Louis went on the Seventh Crusade.

She died in 1252, perhaps to the relief of her daughter-in-law, Margaret of Province, who had a difficult relationship with Blanche who was jealous of any time that Louis spent with Margaret.