João Manuel, Prince of Portugal

Portuguese royalty
House of Aviz-Beja

Manuel I Children include    Miguel da Paz, Prince of Portugal and of Asturias    João, Prince of Portugal (future John III)    Infanta Isabel, Holy Roman Empress    Infanta Beatriz, Duchess of Savoy    Infante Luís, Duke of Beja    Infante Fernando, Duke of Guarda and Trancoso    Cardinal-Infante Afonso    Cardinal-Infante Henrique (future Henry I)    Infante Duarte, Duke of Guimarães    Infanta Maria, Lady of Viseu Grandchildren include    Philip II of Spain (future Philip I of Portugal)    António, Prior of Crato (future Anthony I) (illegitimate)    Infanta Maria of Guimarães, Duchess of Parma and Piacenza    Infanta Catarina of Guimarães, Duchess of Braganza Great-Grandchildren include    Teodósio II, Duke of Braganza    Ranuccio I Farnese of Parma Great-Great-Grandchildren include    John II, Duke of Braganza (future John IV of Portugal) John III Children include    Maria Manuela, Princess of Portugal and of Asturias    João Manuel, Prince of Portugal Grandchildren include    Sebastião, Prince of Portugal (future Sebastian I)    Carlos, Prince of Asturias Sebastian Henry Anthony (disputed king)

Infante D. João of Portugal.

The Infante João Manuel, Prince of Portugal (pronounced [ʒuˈɐ̃ũ mɐnuˈɛɫ]; in English: John Emannuel) (June 3, 1537 – January 2, 1554) 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 we was styled Prince of Portugal. João was born in June 3, 1537 in Évora and became the heir to the throne of Portugal in 1539. He survived his four older brothers who died in childhood but was a sickly teenager. The successive inter-marriages between the houses of Spain and Portugal probably had some responsibility for his ill health. In 1552 he married Joan of Spain (princess of Spain), his first cousin, through both paternal and maternal line, daughter of his paternal aunt Isabel of Portugal and of his maternal uncle Emperor Charles V. João died of what the sources refer to as consumption (tuberculosis) on January 2, 1554, however it is worth mentioning that some historians believe his death occurred as a result of diabetes. Eighteen days later, a posthumous son was born from his marriage: the future King Sebastian I of Portugal. His death at the age of only sixteen was the beginning of the succession problem in Portugal that would end in the loss of independence to Spain in 1580.