[2] The letters of King Philip IV dated 7 April 1299, recount the private agreements between the king and Roger Bernard III, Count of Foix relating to the proposed marriage of Joan (who was ten years old at the time), to the Count's eldest son, Gaston (born 1287).
In October 1301 at Senlis, the marriage contract was signed and Joan was subsequently wed to Gaston de Foix.
In spite of a compromise signed in 1325 in Beaugency, bitter quarrels became more frequent between Joan and her eldest son Gaston who had succeeded his father as Count of Foix.
She was later moved to Orthez, then to Lourdes; finally in 1347, her third eldest son, the Bishop of Lavaur secured her release from prison and she retired to Carbonne.
French historian Jules Michelet suggested a link between Joan's imprisonment in 1331 and the fact that her brother Robert was at the time being sued for forgery and accused of practising witchcraft against the life of King Philip VI.