Duarte, Duke of Guimarães was a Portuguese infante ; the sixth son of King Manuel I of Portugal and his wife Maria of Aragon.
A succession crisis emerged in Portugal in 1580 as a result of the disappearance of the young King Sebastian in the Battle of Alcácer Quibir in 1578 and the death of his great-uncle King Henry in 1580
Ranuccio Farnese Hereditary Duke of Parma
Catherine of Portugal Duchess of Braganza
Philip II King of Spain
António of Portugal Prior of Crato