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.
Joseph I of Portugal
Joseph succeeded to the Portuguese throne in 1750, when he was 36 years old, and almost immediately placed effective power in the hands of Sebastião José de Carvalho e Melo, better known today as the Marquess of Pombal. Indeed, the history of Joseph's reign is really that of Pombal himself. King Joseph also declared his eldest daughter Maria Francisca as the official heiress of the throne and proclaimed her Princess of Brazil. By this time, the king did not believe he would ever father a son by his queen.