[3] Joan herself married at Olite on 12 November 1402 to John, Viscount of Castellbò, the heir to the County of Foix in France.
A month after her wedding, Joan was recognized as heiress presumptive to the throne of Navarre at Olite on 3 December 1402.
[4] There the Estates of Navarre swore an oath to Joan and John as their future sovereigns.
This was after the early death of Joan's only brothers, Charles and Louis, in quick succession earlier in the year.
[4] Her younger sister Blanche became heiress presumptive to the throne of Navarre, and succeeded their father Charles III on 8 September 1425.