Infante Diogo, Duke of Viseu

Portuguese royalty
House of Avis

John I
Children
   Edward I
   Peter, Duke of Coimbra
   Henry the Navigator
   Isabella, Duchess of Burgundy
   John, Lord of Reguengos de Monsaraz
   Ferdinand the Saint Prince
Grandchildren include
   Isabella, Queen of Portugal
Edward
Children
   Afonso V
   Ferdinand, Duke of Viseu
   Eleanor, Holy Roman Empress
   Catherine
   Joan, Queen of Castile
Grandchildren include
   Manuel I
   Eleanor, Queen of Portugal
   Isabella, Duchess of Braganza
Great-Grandchildren include
   James, Duke of Braganza, Prince of Portugal
Afonso V
Children include
   John, Prince of Portugal
   Joan, Princess of Portugal
   John II
John II
   Afonso, Prince of Portugal

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

In 1472, when his older brother John, Duke of Viseu, died without issue, Diogo inherited his titles and estates as 4th Duke of Viseu and 3rd Duke of Beja.

Diogo was a popular personality at the court of his cousin King John II, and together with Duke Fernando 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 of Braganza, husband of Isabella of Viseu, the sister of John II, 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 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 Kingdom of Castile, where he had a love affair 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.

Contents

Ancestry

See also

External links

Bibliography

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

Infante Diogo, Duke of Viseu
Cadet branch of the House of Burgundy
Born: ? 1450 Died: ? 1484
Portuguese nobility
Preceded by
John of Viseu, 2nd Duke of Beja

Duke of Beja

1472–1484
Succeeded by
Manuel of Viseu, 3rd Duke of Beja
Preceded by
John, 3rd Duke of Viseu

Duke of Viseu

1472–1484
Succeeded by
Manuel, 5th Duke of Viseu