On 17 November 1197, Alfonso IX married his first cousin once removed, the infanta Berengaria of Castile. Berengeria was the daughter of King Alfonso VIII of Castile and his wife Queen Leonor of England. Her paternal grandfather, Sancho III of Castile, had been a brother of Alfonso's own father Ferdinand II of León. Thus, both Alfonso IX and Berengaria belonged to the same dynasty or family. The marriage was annulled on grounds of consanguinity, but not before five children had been born, namely: Eleanor (119811 November 1202). Constance (died in 1242), became a nun at the Abbey of Santa María la Real de Las Huelgas, Burgos, where she died. Ferdinand III of Castile (1199/12011252). King of Castile in 1217 after the death of Henry I of Castile and of León in 1230 after the death of his father. Alfonso (died in 1272), Lord of Molina jure uxoris due to his first marriage to Mafalda González de Lara. Berengaria of León (died in 1237), in 1224 married John of Brienne,
On 17 November 1197, Alfonso IX married his first cousin once removed, the infanta Berengaria of Castile. Berengeria was the daughter of King Alfonso VIII of Castile and his wife Queen Leonor of England. Her paternal grandfather, Sancho III of Castile, had been a brother of Alfonso's own father Ferdinand II of León. Thus, both Alfonso IX and Berengaria belonged to the same dynasty or family. The marriage was annulled on grounds of consanguinity, but not before five children had been born, namely: Eleanor (119811 November 1202). Constance (died in 1242), became a nun at the Abbey of Santa María la Real de Las Huelgas, Burgos, where she died. Ferdinand III of Castile (1199/12011252). King of Castile in 1217 after the death of Henry I of Castile and of León in 1230 after the death of his father. Alfonso (died in 1272), Lord of Molina jure uxoris due to his first marriage to Mafalda González de Lara. Berengaria of León (died in 1237), in 1224 married John of Brienne,