Antonio Pérez del Hierro (1540–Paris, 7 April 1611)[1] was a Spanish statesman and secretary of king Philip II of Spain.

Antonio later attended the most prestigious universities such as Alcalá de Henares, Salamanca, Leuven, Venice and Padua.

During his first ten years as secretary, Antonio Pérez had great influence over king Philip who valued his advice.

With the death of the Prince of Eboli in 1573, Antonio Pérez became the leader of that faction in accord with the widow, Ana de Mendoza, the one-eyed Princess of Éboli.

King Philip was suspicious of the designs of his half-brother Don Juan of Austria and Antonio Pérez exploited this suspicion to his own benefit.

Nevertheless, he could not arrest him immediately as Pérez was a powerful man with information which could damage the king, including the murder of Escobedo.

The Princess of Éboli, as a proud woman who confronted the king, was kept imprisoned in different places, mostly in her palace in Pastrana, for the rest of her days.

While at Turégano Antonio Pérez enjoyed relative freedom, his wife and children went to live with him and he soon assembled, as was his custom, a retinue of followers.

This group set up their base in the nearby village of Muñoveros and did manage to enter the castle in the middle of the night but the governor and his guard, outnumbered and against all odds, tricked them and convinced them to give up their attempt.

Pérez knew that his safety depended on having these papers and would not produce them and the king's tactics alternated between punishing him or giving him more freedom.

With two loyal men, he rode all night trying to gain the border of Aragon, a separate kingdom with laws that protected him.

In spite of his age and his poor physical state after being tortured, they rode all night changing horses along the Royal Posts.

There he was put in the prison of manifestados subject to the justice of Aragon which for him meant protection from the king and the judicial process in Castile.

To prevent any escape attempt a special guard was placed outside the prison of manifestados by order of the king and Antonio Pérez used this to his advantage by playing the issue as one of Castile infringing on the sovereignty of Aragon.

The courts of Aragon hindered the judicial process and it seemed Antonio Pérez would be found innocent so the king's accusation was withdrawn and a new, similar, accusation was presented by the king's representative in Aragon, Iñigo de Mendoza y de la Cerda, Marquis of Almenara.

The king then resorted to the farce of accusing Antonio Pérez of heresy through the Inquisition which was an ecclesiastical organization and had jurisdiction in both Castile and Aragon.

On 13 May, Antonio Pérez was moved to a prison in the Aljafería which caused riots of the people of Aragon who considered this an affront and a violation of their laws.

In the riots, the marquis of Almenara, representative of the king, was killed and soon Antonio Pérez was triumphantly returned to the prison of manifestados.

The king ordered that the Chief Justice, Juan de Lanuza y Urrea, be executed without trial and on December 20, 1591, his head was exhibited for all the terrified people to see.

On the night of 23 November, disguised as a shepherd and in heavy snow, Antonio Pérez crossed the Pyrenees into the Kingdom of Bearn-Navarre.

Gustav Ungerer argued that there were many similarities between Perez and Armado, including their prose style and their love life.

Pérez's Relaciones along with the Apologia written by William of Orange in 1580, are largely responsible for the Black Legend that has grown around Philip II.