John of Foix (1450 – 1500, Étampes, France) was a younger son of Count Gaston IV of Foix and Queen Eleanor of Navarre.
[1] His elder brother was Gaston, Prince of Viana.
He married Marie of Orléans, sister of Louis XII, in 1483.
[1] They had two children: Following the death of his nephew, King Francis of Navarre in 1483, John claimed Navarre as the next male in the succession, challenging Francis' sister and heiress, Queen Catherine.
[2] Although the Salic law had never been enforced in the Kingdom of Navarre, the result of this claim was a civil war in Navarre, which only ended in Catherine's favour in 1497, with John being forced to give up his claim.