John Manuel was a Portuguese infante, the eighth son of King John III of Portugal by his wife Catherine of Habsburg (House of Habsburg), daughter of Philip of Burgundy and Joanna of Castile. As the heir to the throne he was styled Prince of Portugal.
Juana of Spain, Granddaughter of Juana of Castile, Great-Niece of Catherine of Aragon Joan of Spain (in Castilian, Juana de Austria, 24 June 1535 - 7 September 1573), Infanta of Spain, of the Habsburg family. She was born in Madrid to Charles V, Holy Roman Emperor (who was the first king of united Spain, officially King of Aragon and King of Castile) and his consort Infanta Isabel of Portugal, daughter of King Manuel I of Portugal.
'Bianca Maria Sforza was Holy Roman Empress as the second wife of Maximilian I, Holy Roman Emperor' by German artist Bernhard Stigel via It's About Time: A little gossip - Bianca Maria Sforza married at widow at Empress of the Holy Roman Empire at 22
(Sister of Catherine of Aragon) Maria, Queen of Portugal - born 29 June 1482 - 7 March She was the third surviving daughter of Isabella of Castile and Ferdinand II of Aragon (the Catholic monarchs). Maria married her sister's widower Manuel I of Portugal.