Diogo, Duke of Viseu

Infante Diogo of Viseu (1450–1484) was the second son of Infante Fernando, Duke of Viseu, and his wife Beatriz of Portugal.

History

In 1472, when his older brother John, Duke of Viseu, died without issue, Diogo inherited his titles and estates as Duke of Viseu and Duke of Beja.

Diogo was a popular personality at the court of his cousin King John II, and together with Duke Fernando II of Braganza, he was the main target of King John’s centralization policies. John II sought to limit the power of the upper nobility, which had increased greatly during the reign of John's father Afonso V of Portugal.

Duke Fernando II of Braganza, husband of Isabella of Viseu, the sister-in-law of King John II of Portugal and Diogo's sister, was the first victim of John's efforts against the Portuguese nobility. He was imprisoned, tried and executed in Évora. Once his sister Eleanor of Viseu was married to the king, Diogo thought he was protected from the king’s anger.

On two occasions, the king’s life was in danger and as Diogo of Viseu remained the leader of the upper nobility against the King’s policies, John II accused him of high treason and personally killed him.

After the execution, King John II called the duke’s younger brother, Infante Manuel of Viseu, and showed him his brother’s body. He promised Manuel that he would consider him his own son. At that moment, Manuel inherited his brother Diogo's titles and estates.

Duke Diogo never married, but when he was quite young he visited the Crown of Castile, where he had a love affair with Doña Leonor de Sotomaior y Portugal (great-granddaughter of King Pedro I of Portugal). With her he had a natural son, Afonso de Portugal. King Manuel I of Portugal granted this nephew, Afonso de Portugal, the position of 8th Constable of Portugal. Afonso’s daughter and heir, Beatrice of Lara, married the 3rd Marquis of Vila Real.

Ancestry

Family of Diogo, Duke of Viseu

16. Peter I of Portugal (= 24)               8. John I of Portugal (= 12, 28)                       17. Teresa Lourenço (= 25)               4. Edward of Portugal                             18. John of Gaunt, 1st Duke of Lancaster (= 26)               8. Philippa of Lancaster (= 13)                       19. Blanche of Lancaster (= 27)               2. Infante Fernando, Duke of Viseu                                   20. John I of Castile               10. Ferdinand I of Aragon                       21. Eleanor of Aragon               5. Eleanor of Aragon                             22. Sancho Alfonso, 1st Count of Alburquerque               11. Eleanor of Alburquerque                       23. Beatrice of Portugal               1. Infante Diogo, Duke of Viseu                                         24. Peter I of Portugal (= 16)               12. John I of Portugal (= 8, 28)                       25. Teresa Lourenço (= 17)               6. Infante João, Lord of Reguengos                             26. John of Gaunt, 1st Duke of Lancaster (= 18)               13. Philippa of Lancaster (= 9)                       27. Blanche of Lancaster (= 19)               3. Infanta Beatriz of Portugal                                   28. John I of Portugal (= 8, 12)               14. Afonso, 1st Duke of Braganza                       29. Inês Pires Esteves               7. Isabella of Barcelos                             30. Nuno Álvares Pereira               15. Beatriz Pereira de Alvim                       31. Leonor de Alvim

See also

• Duke of Beja
• Duke of Viseu
• List of Portuguese Dukedoms

External links

• Genealogy of Diogo, 4th Duke of Viseu, in Portuguese

Bibliography

”Nobreza de Portugal e do Brasil” – Vol. III, pages 544 and 545. Published by Zairol Lda., Lisbon 1989.

Diogo, Duke of Viseu House of Aviz Cadet branch of the House of Burgundy Born: ? 1450 Died: ? 1484
Portuguese nobility
Preceded by Infante John	Duke of Beja 1472–1484	Succeeded by Infante Manuel
Preceded by Infante John	Duke of Viseu 1472–1484	Succeeded by Infante Manuel