Career
Beatrice"s paternal grandparents were Ferdinand III of Castile and Elisabeth of Hohenstaufen, herself daughter of Philip of Swabia and Irene Angelina. Beatrice was originally betrothed to John II, Margrave of Brandenburg. Her betrothal was arranged by her father to attract the support of Brandenburg for his candidacy for the throne of Germany.
The engagement was however broken official
Beatrice married in Murcia in August 1271 to William VII, Marquess of Montferrat. He had been married twice already but only had a daughter Margaret, who married Beatrice"s brother John.
Beatrice and William had the following children:
a son (1272–1273), died young
a son (1272–1273), died young and twin of previous
Yolande (1274–1317), married Andronikos II Palaiologos and had issue
John I (c1275-1305), succeeded his father as Marquess
Alessina (died before 1305), married Poncello Orsini.