Diogo of Portugal

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

Diogo of Portugal (1425–1443) was a Portuguese infante, son of John, Lord of Reguengos de Monsaraz, infante of Portugal, and of his wife (and niece) Isabella of Braganza. Through his father Diogo was grandson of king John I of Portugal and through his mother he was grandson of Alphonse, first duke of Braganza.

Following his father's death (1442) he received the title of Constable of Portugal, and was also elected, in 24 January 1443, as 11th. Master of the Order of Santiago.

This was one of the causes of the quarrel between the regent infante Pedro, Duke of Coimbra and his half-brother Afonso, Duke of Braganza, once Afonso wanted the Constable position to his own son.

Diogo died unmarried later the same year, without issue.

Ancestry

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
16. Afonso IV of Portugal
 
 
 
 
 
 
 
8. Peter I of Portugal (=#24)
 
 
 
 
 
 
 
 
 
 
 
17. Beatrice of Castile
 
 
 
 
 
 
 
4. John I of Portugal
 
 
 
 
 
 
 
 
 
 
 
 
 
 
18. Lourenço Martins
 
 
 
 
 
 
 
9. Teresa Lourenço (=#25)
 
 
 
 
 
 
 
 
 
 
 
19. Sancha Martins
 
 
 
 
 
 
 
2. John, Lord of Reguengos de Monsaraz
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
20. Edward III of England
 
 
 
 
 
 
 
10. John of Gaunt, 1st Duke of Lancaster
 
 
 
 
 
 
 
 
 
 
 
21. Philippa of Hainault
 
 
 
 
 
 
 
5. Philippa of Lancaster
 
 
 
 
 
 
 
 
 
 
 
 
 
 
22. Henry of Grosmont, 1st Duke of Lancaster
 
 
 
 
 
 
 
11. Blanche of Lancaster
 
 
 
 
 
 
 
 
 
 
 
23. Isabel de Beaumont
 
 
 
 
 
 
 
1. Isabella of Portugal
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
24. Peter I of Portugal (=#8)
 
 
 
 
 
 
 
12. John I of Portugal
 
 
 
 
 
 
 
 
 
 
 
25. Teresa Lourenço (=#9)
 
 
 
 
 
 
 
6. Afonso, 1st Duke of Braganza
 
 
 
 
 
 
 
 
 
 
 
 
 
 
26. Pero Esteves, o Barbadão
 
 
 
 
 
 
 
13. Inês Pires
 
 
 
 
 
 
 
 
 
 
 
27. Maria Anes
 
 
 
 
 
 
 
3. Isabella of Braganza
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
28. Álvaro Gonçalves Pereira, Prior of Crato
 
 
 
 
 
 
 
14. Nuno Álvares Pereira
 
 
 
 
 
 
 
 
 
 
 
29. Iria Gonçalves do Carvalhal
 
 
 
 
 
 
 
7. Beatriz Pereira de Alvim
 
 
 
 
 
 
 
 
 
 
 
 
 
 
30. João Pires de Alvim
 
 
 
 
 
 
 
15. Leonor de Alvim
 
 
 
 
 
 
 
 
 
 
 
31. Branca Pires Coelho
 
 
 
 
 
 

External links

Bibliography

"Nobreza de Portugal e do Brasil" – Vol. I, page 297. Published by Zairol Lda., Lisbon 1989.