Infanta Branca of Portugal, daughter of King Afonso III of Portugal (born 1259)

Blanche of Portugal, was an infanta, the firstborn child of King Afonso III of Portugal and his second wife Beatrice of Castile. Named after her great-aunt Blanche of Castile, queen of France, Blanche was the Lady of Las Huelgas, Montemor-o-Velho, Alcocer and Briviesca, the city which she founded.

Afonso III, called the Boulonnais, was King of Portugal and the first to use the title King of Portugal and the Algarve, from 1249. He was the second son of King Afonso II of Portugal and his wife, Urraca of Castile; he succeeded his brother, King Sancho II of Portugal, who died on 4 January 1248.