Dinis of Braganza, Count of Lemos
Dinis of Braganza( 1481 – 1516) was the younger son of Fernando II, Duke of Braganza and Isabella of Viseu who was a daughter of Infante Fernando, Duke of Viseu and Beatrice of Portugal.
Beatriz Pereira de Alvim
Beatriz Pereira de Alvim (1380–1414) was a Portuguese noblewoman, the only child of Nuno Álvares Pereira and his wife Leonor de Alvim.
On 8 November 1401, she married Afonso, Count of Barcelos, illegitimate son of king John I of Portugal.
She died before her husband became Duke of Braganza.
Afonso and Beatriz had three children.
Isabel of Braganza, Duchess of Guimarães
Dona Isabel of Braganza (1514 – 16 September 1576) was a member of the House of Braganza, daughter of Jaime, Duke of Braganza (a nephew of Manuel I of Portugal) and Leonor Pérez de Guzmán.
Isabella of France, Dauphine of Viennois
" For other persons named Isabella of France, see Isabella of France( disambiguation)" Isabella of France and Burgundy( 1310 – April 1348) was the daughter of Philip V of France and Joan II, Countess of Burgundy.
João of Braganza, Marquis of Montemor-o-Novo
João of Braganza, born ca. 1430, was the second son of Fernando I, Duke of Braganza and of his wife, the duchess Joan of Castro.
Infanta Maria Adelaide of Portugal
Doña Maria Adelaide of Braganza, Infanta of Portugal,( 31 January 191224 February 2012) was a member of the royal house of Braganza, daughter of Miguel, Duke of Braganza and Princess Maria Theresa of Löwenstein- Wertheim- Rosenberg.
Jaime, Duke of Braganza
Jaime of Braganza( 1479 – 20 September 1532) was the 4th Duke of Braganza and the 2nd Duke of Guimarães, among other titles.
He is known for reviving the wealth and power of the House of Braganza which had been confiscated by King John II of Portugal.
Diogo, Constable of Portugal
Diogo of Portugal( 1425–1443) was a Portuguese royal prince, who briefly served as Constable of Portugal and Master of the Order of Santiago.
Diogo was the eldest son of John, Lord of Reguengos de Monsaraz, Infante of Portugal, and of his wife( and niece) Isabella of Barcelos.
Through his father, Diogo was the grandson of King John I of Portugal and through his mother, the grandson of Afonso of Barcelos( future first duke of Braganza).
John of Reguengos had been the master of the Order of Santiago since 1418 and Constable of Portugal since 1431.
Upon John's premature death in October 1442, the Portuguese regent, Peter of Coimbra decided to appoint John's son Diogo as the new Constable of Portugal.
Diogo was elected on 24 January 1443, as 11th Master of the Order of Santiago.
Diogo died a few days later, without issue.
Peter appointed his own son, also named Peter, to succeed him as constable.
These appointments were contested by Diogo's half- uncle( and grandfather), Afonso, Count of Barcelos.
Afonso had married the daughter of the late beatified constable Nuno Álvares Pereira, and believed their son, Afonso of Ourem, had superior rights to succeed as Constable of Portugal.
Peter of Coimbra challenged Barcelos and Ourem to provide documentary proof of the legitimacy of this lineage( which they were unable to produce).
Peter of Coimbra attempted to mollify them by creating the title of Duke of Braganza, and investing it in Afonso of Barcelos.
However, this failed to heal the breach between Peter and Afonso, which would only grow with time.
Teodósio I, Duke of Braganza
Dom Teodósio I of Braganza (1510 – 22 September 1563) was the 5th Duke of Braganza, among other titles.
He is known for ceding the title of Duke of Guimarães to Infante Duarte of Aviz, alongside some of the wealth and properties of the House of Braganza.
Isabel of Barcelos
Isabel of Barcelos (October 1402 – 26 October 1466), also known as Isabel of Braganza, was a lady of the Portuguese nobility during the Late Middle Ages.
She was the daughter of Afonso I, Duke of Braganza and Beatriz Pereira de Alvim, and she married Infante John, Lord of Reguengos de Monsaraz, her half-uncle, son of John I of Portugal.

Question: Who is Isabel Of Barcelos's maternal grandfather?
Answer: Nuno Álvares Pereira