Pedro de Deza
He studied Latin under Juan Ulloa Pereira before attending the Colegio Viejo de San Bartolomé at the University of Salamanca, where he studied law. After completing his studies, he became a professor of law at the Colegio Viejo de San Bartolomé.
Early ecclesiastical career
He spent eight years as the vicar general of the Archbishop of Santiago de Compostela. In 1556, he became an oidor in the Royal Audiencia and Chancillería of Valladolid. During the pontificate of Pope Paul IV (1555–59), he served as Archdeacon of Calatrava la Vieja. He was also an auditor of the Spanish Inquisition. In 1556, he became the president of the Kingdom of Granada, in which capacity he participated in the suppression of the Morisco Revolt of 1568-71. He became president of the Council of Valladolid in 1578.
Years as cardinal
On the recommendation of Philip II of Spain, Pope Gregory XIII made him a cardinal priest in the consistory of February 21, 1578. He received the red hat and the titular church of San Ciriaco alle Terme Diocleziane on June 22, 1580. He resided in Rome from 1580 on. On January 9, 1584, he opted for the titular church of Santa Prisca.
He participated in the papal conclave of 1585 that elected Pope Sixtus V. The new pope named him inquisitor general of the Roman Inquisition on November 19, 1586. On April 20, 1587, he opted for the titular church of Saint Jerome of the Croats. In 1590, he participated in both the first papal conclave of 1590 that elected Pope Urban VII, and in the second papal conclave of 1590 that elected Pope Gregory XIV. He went on to participate in the papal conclave of 1591 that elected Pope Innocent IX, and the papal conclave of 1592 that elected Pope Clement VIII.
On April 24, 1600, he opted for the order of cardinal bishops, taking the suburbicarian see of Albano. He was consecrated as a bishop by Pope Clement VIII in St. Peter's Basilica on June 18, 1600.
He died in Rome on August 27, 1600. He was initially buried in San Lorenzo in Lucina. Later, according to the terms of his will, his remains were transferred provisionally to the hermitage of Villaguer in Toro, Zamora. Finally, he was buried in the convent of the Discalced Carmelites in Toro.