Background
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.
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.
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.