Juan Alfonso Pérez de Guzmán, 6th Duke of Medina Sidonia
Juan Alfonso Pérez de Guzmán y de Guzmán-Zúñiga, 6th Duke of Medina Sidonia (24 March 1502 – 26 November 1558) was the son of Juan Alfonso Pérez de Guzmán, 3rd Duke of Medina Sidonia, half brother of Enrique Pérez de Guzmán, 4th Duke of Medina Sidonia, and the brother of Alfonso Pérez de Guzmán, 5th Duke of Medina Sidonia.
Upon his brother's death in 1549, he became Duke of Medina Sidonia.
In 1518 he married his brother's wife, Ana de Aragón (d. 1528), daughter of Alonso de Aragón, and had issue:
As Don Juan Carlos predeceased his father in 1556, the title passed to his eldest son Alonso Pérez de Guzmán, 7th Duke of Medina Sidonia.
Manuel Pérez de Guzmán, 12th Duke of Medina Sidonia
Manuel Pérez de Guzmán y Pimentel, 12th Duke of Medina Sidonia( 1671 – 1721) became Duke of Medina Sidonia in 1713.
He was married in 1687, aged 16, to the 17- year- old Luisa Maria de Silva Mendoza.
She was a daughter of Gregorio Maria Domingo, the 5th Duke of Pastrana, 5th Duke of Estremera and 9th Duke of el Infantado.
They had 10 children.
The duke was awarded the title of a Knight of the Order of the Golden Fleece, and served as Captain General of Catalonia between 1690 and 1693.
Juan Manuel Pérez de Guzmán, 8th Duke of Medina Sidonia
Juan Manuel Pérez de Guzmán y Silva (7 January 1579 – 1636) was a Spanish noble and 8th Duke of Medina Sidonia.
He was the son of Alonso Pérez de Guzmán, 7th Duke of Medina Sidonia, commander-in-chief of the Spanish Armada and Ana de Silva y Mendoza, daughter of Ana de Mendoza, Princess of Éboli.<br
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He married in 1598, aged 19, Juana de Sandoval, daughter of the Duke of Lerma, a favourite of Philip III of Spain.
He was promoted to Knight of the Order of the Golden Fleece in 1615, aged 36 and 34 years after his father.
In the same year he became 8th Duke of Medina Sidonia.
In 1625 he commanded, from Jerez de la Frontera, the military operations neutralizing the attack on Cadiz by a Dutch-English Fleet, commanded by Sir Edward Cecil.
His eldest daughter Luisa de Guzmán (1613–1666) became queen-consort of Portugal when her husband John II, 8th Duke of Braganza, became John IV, the first King of Portugal of the House of Braganza in 1640.
In order to encourage her husband when the Portuguese nobility offered him the crown of Portugal, Luisa is known for her phrase: better Queen for one day, than Duchess all my life.
His granddaughter Catherine of Braganza married King Charles II of England.
Pedro Pérez de Guzmán, 1st Count of Olivares
Pedro Pérez de Guzmán y Zúñiga( Sp.:" Don Pedro Pérez de Guzmán y Zúñiga, primer Conde de Olivares") was the founder of the House of Olivares, a cadet branch of the House of Medina Sidonia.
Enrique Pérez de Guzmán, 4th Duke of Medina Sidonia
Don Enrique Pérez de Guzmán y Fernández de Velasco, 4th Duke of Medina Sidonia( died 1512) was the son of Juan Alfonso Pérez de Guzmán, 3rd Duke of Medina Sidonia.
He was Duke of Medina Sidonia from 1507.
No issue by his wife María Téllez Girón.
Juan Claros Pérez de Guzmán, 11th Duke of Medina Sidonia
Juan Claros Pérez de Guzmán y Fernández de Córdoba, 11th Duke of Medina Sidonia( 1642–1713) became Duke of Medina Sidonia in 1667 upon the death of his half- brother Gaspar Juan Pérez de Guzmán, 10th Duke of Medina Sidonia.
In around 1670 he married Antonia Teresa Pimentel( b. 1646).
She was the daughter of the 8th Duke of Benavente and already twice widowed.
Her first husband Andrea Fabrizio Pigntelli d ´ Aragona, Prince of the Holy Roman Empire, 5th Prince of Noia and 7th Duke of Monteleone was killed in battle in 1677.
Her second was Jaime Francico Víctor Fernández de Híjar, 5th Duke of Híjar.
He was Mayordomo mayor to King Charles II and later Caballerizo mayor to King Philip V.
The duke also married for a second time to a Mariana Núñez Felipez de Guzmán y Velez, the 3rd Duchess of Medina de las Torres, whose father, Ramiro, had been Viceroy of Naples.
Gaspar Juan Pérez de Guzmán, 10th Duke of Medina Sidonia
Gaspar Juan Pérez de Guzmán y Guzmán, 10th Duke of Medina Sidonia( 1630 – 1667) was Duke of Medina Sidonia from 1664 to 1667.
He married Antonia, daughter of Luis Méndez de Haro, 6th Marquis of Carpio.
He died without issue, and the title passed to his younger half brother.
Gaspar Alfonso Pérez de Guzmán, 9th Duke of Medina Sidonia
Gaspar Alfonso Pérez de Guzmán y Sandoval, 9th Duke of Medina Sidonia (1602–1664) was a Spanish nobleman who became Duke of Medina Sidonia in 1636, upon the death of Juan Manuel Pérez de Guzmán, 8th Duke of Medina Sidonia.
In 1622, aged 20, he married his 14-year-old aunt Ana María de Guzmán (1607–1637), having four children by her, of which only the youngest, Gaspar Juan, survived to inherit the title.
In 1639, the 9th Duke was married for a second time to Seville noblewoman Juana Fernández de Córdoba, but only after signing documents giving the considerable amount of 20,000 Ducados to Margarita Marañon, on condition she become a nun near his palace in Sanlúcar de Barrameda, later in a Dominican convent.
It is said she was the mother of his illegitimate daughter, Luisa.
In 1640, his sister Luisa of Guzman became the new Queen of Portugal, as the wife of the former Duke of Braganza, now John IV of Portugal.
In 1641 the 9th Duke led the Andalusian rebellion against Spanish rule.
Though both Portugal and Catalonia had strong cultural identities, an historical record of independence, and popular support, Andalusia did not, and the rebellion failed.
The duke had the support of his brother-in-law, John IV of Portugal, but the promised naval aid from France and the Netherlands did not arrive.
The king of Spain forgave his treason, but the previous prestige of his house was only regained by his successor.
Alfonso Pérez de Guzmán, 5th Duke of Medina Sidonia
Alfonso Pérez de Guzmán y de Guzmán- Zúñiga, 5th Duke of Medina Sidonia( d. 1549) was the son of Juan Alfonso Pérez de Guzmán, 3rd Duke of Medina Sidonia and became Duke of Medina Sidonia in 1512 when his half brother, Enrique Pérez de Guzmán, 4th Duke of Medina Sidonia died childless.
Declared" impotent and stupidmentecato", in 16th- century Spanish language) by King Charles I of Spain in 1518, his wife Ana de Aragón was the daughter of Alonso de Aragón, Archbishop of Zaragoza, the illegitimate son of Ferdinand II of Aragon.
After the 5th duke's death, his widow married his brother Juan Alfonso, the 6th Duke.
Pedro Téllez-Girón, 3rd Count of Ureña
Pedro Téllez- Girón y Fernández de Velasco or Pedro Girón( died Seville, April 25, 1531), was a Spanish noble, 3rd Count of Ureña and a leader of the Revolt of the Comuneros.
He was the son of Juan Téllez- Girón, 2nd Count of Ureña and Leonor de la Vega Velasco, daughter of Pedro Fernández de Velasco, 2nd Count of Haro.
He married Mencía de Guzmán, daughter of Juan Alfonso Pérez de Guzmán, 3rd Duke of Medina Sidonia.
When his brother- in- law Enrique Pérez de Guzmán, 4th Duke of Medina Sidonia, died in 1512 without issue, Pedro Girón unsuccessfully claimed the title of Medina Sidonia through his wife.
Pedro stated that Alonso Pérez de Guzmán, son of the third Duke and his second wife, was an illegitimate child.
Pedro Girón had contacted the" Junta de Tordesillas" to defend his claims on the Duchy of Medina Sidonia, and became thus one of the leaders of the comuneros, together with Juan de Padilla and Antonio de Acuña.
He was proclaimed unanimously Capitán General of the rebel army.

Question: What is the date of birth of Gaspar Alfonso Pérez De Guzmán, 9Th Duke Of Medina Sidonia's father?
Answer: 7 January 1579