She passed on the regency of Navarre to Philip III of France, her cousin and her daughter's prospective father-in-law, but retained the administration of Champagne.

[1] Henry was governing his brother's realm when King Theobald and Queen Isabella left to join the Eighth Crusade.

[5] A daughter named Joan, born the same year, remained the royal couple's only child and was recognized as heir presumptive by the King and the Estates.

The death of two kings within five years and accession of an infant queen, the first woman to rule Navarre and Champagne alike, triggered a political crisis.

Both Alfonso X of Castile and Peter III of Aragon wanted to secure Navarre for their respective houses either by marriage with Joan or by force.

While Peter contemplated a marriage with a cousin of Joan, Alfonso moved his army to Navarre and started besieging Viana.

[3] Blanche remained in Pamplona at least until 14 April, but then fled the kingdom, taking Joan with her, on the pretext of visiting her daughter's fiefs in the north of France.

In May 1275, Queen Blanche signed the Treaty of Orléans, by which she promised Joan's hand in marriage to one of the older two sons of the King of France, either Louis or Philip.

[3] The marriage was orchestrated by the dowager queen of France Margaret of Provence, who wished to secure a wealthy bride for her nephew.