[4] Her exact date of birth was not recorded, but she certainly was born in late 1247 or early 1248 since her father, who financially supported the Monastery of Santa María de Sigena, stipulated in his will in January 1248 that if he had another son, he should become a knight Templar and if the child was a daughter, she should enter Santa María de Sigena as a nun.

[7] The formal wedding took place on 28 May 1262 at the city of Clairmont (currently Clermont-Ferrand); by that time, Philip was already the heir apparent to the French throne due to the death of his older brother, Louis, in 1260.

Having accompanied her husband and father-in-law on the Eighth Crusade against Tunis in July 1270, Isabella became queen of France the following month on the death of King Louis IX.

On their way home, while crossing the Savuto river near Martirano in Calabria, on 11 January 1271 she suffered a fall from her horse: six months pregnant with her fifth child, she gave birth prematurely to a son, who died soon after.

[8] Firstly, she was buried at Cosenza Cathedral alongside her newborn son,[9] and then in the royal necropolis in the Basilica of St Denis.