Kurš datēja Joan of Portugal?

Joan of Portugal (Portuguese: Joana [ʒuˈɐnɐ]; 31 March 1439 – June 13, 1475) was the Queen of Castile as the second wife of King Henry IV of Castile. The posthumous daughter of King Edward of Portugal and Eleanor of Aragon, she was born in the Quinta do Monte Olivete Villa, Almada.

Beltrán de la Cueva y Alfonso de Mercado, 1st Duke of Alburquerque (c. 1443 – 1 November 1492) was a Spanish nobleman who is said to have fathered Joanna, the daughter of Henry IV of Castile's wife Joan of Portugal. His alleged daughter, called "la Beltraneja", was deprived of the crown of Castile because of the uncertainty regarding her parentage.