Beatrice of Portugal was born around 7 February 1373 as the daughter of Ferdinand I of Portugal and Leonor Telles de Meneses. She had two younger brothers, who both died young in 1380 and 1382. She would thus prove to be their only surviving child. Ferdinand I also had an illegitimate daughter with a mistress. To ensure Beatrice’s succession Ferdinand allied himself with John I of Castile, promising Beatrice in marriage to him and uniting the two crowns.
However, this was easier said than done. When Ferdinand I died in 1383 Beatrice was only 11 years old and just recently married to John I of Castile. In what would be known as the 1383-1385 crisis Portugal was effectively without a monarch. Though John I of Castile invaded Portugal claiming it in right of his wife, in the end, Ferdinand’s illegitimate brother John claimed the throne of Portugal and became John I of Portugal with the defeat of Castile at the Battle of Aljubarrota.
Beatrice never ceased to call herself Queen of Portugal, but her claim was never realised. Beatrice and John remained childless, though John did have children from a previous marriage. The throne should have passed to (I presume) the descendants of Maria of Portugal, who was Queen of Castile. Her senior line was Catherine of Lancaster, who was married to John I’s son from his previous marriage to Eleanor of Aragon, Henry III of Castile as the other direct line of claimants is presumed to be illegitimate.
Beatrice appears quite forgotten, and her exact date of death is not even recorded. She died circa 1420, and she was buried at the Monastery of Sancti Spiritus in Toro.
The accession of John I of Portugal did ensure Portugal’s independence from Castile, though we will never know how Portugal would have fared in union with Castile.