[1] She was the youngest daughter of Sancho VI of Navarre[2] and Sancha of Castile,[3] who died in 1179, about two years after Blanche's birth.

The conflict with the Briennes broke into open warfare in 1215, in what became known as the Champagne War of Succession, and was not resolved until after Theobald came of age in 1222.

Prince Louis then proclaimed in a letter to Jean of Brienne, that neither he nor King Philip would hear a challenge against Theobald IV's claim until he was twenty-one.

Blanche had also arranged the dowry of Henry II's elder daughter Alice of Champagne, when she married the young Hugh I of Cyprus.

In the 1230s, in order to settle with Alice, Theobald IV had to sell his overlordship over the counties of Blois, Sancerre, and Châteaudun to Louis IX of France.

[8] After Blanche's death, her brother in retirement remained as King of Navarre and her son Theobald continued as Count of Champagne.