Manuel I of Portugal
Manuel's mother was the granddaughter of King John I of Portugal, whereas his father was the second surviving son of King Edward of Portugal and the younger brother of King Afonso V of Portugal. In 1495, Manuel succeeded his first cousin, King John II of Portugal, who was also his brother-in-law, as husband to Manuel's sister, Eleanor of Viseu.
Manuel, Prince of Portugal (1531–1537)
In 1535, his father officially designated him as Prince of Portugal, taking the place of his eldest sister Infanta Maria Manuela. However, after his premature death at six years old, his younger brother Infante Filipe became the next Prince of Portugal.