The concept of “treason” in the history of Spain depends on the political context of each era, but in all cases, there is a common element: decisions that harmed the State, the territory, or its population for personal gain or that of foreign powers.
Below is a list of those considered "the worst traitors of Spain."
Bellido Dolfos (11th century)
Medieval chronicles recount that in 1072, he assassinated King Sancho II of Castile during the siege of Zamora.
After earning his trust, he killed him from behind and fled to the city.
His act allowed for the continued resistance of Zamora against the Castilian king.
It is considered treason because he deceived the monarch and assassinated him by exploiting his proximity.
Juan Pacheco (1419–1474)
During the reign of Henry IV of Castile, he manipulated the monarch to control power and participated in the Farce of Ávila (1465), where an attempt was made to symbolically dethrone him.
Furthermore, he negotiated with Portugal and Aragon to strengthen his personal position.
His treason lies in the fact that he provoked deliberate political instability and conspired with external powers for his own benefit.
Gonzalo Guerrero (1470–1536)
After shipwrecking in the Yucatán in 1511, he was captured by the Maya and eventually integrated fully into their society: he adopted their customs, got tattoos, married, and had children, eventually being recognized as a military leader.
When Hernán Cortés arrived in 1519 and offered him the chance to return, Guerrero refused. He not only remained with the Maya but participated in the armed defense against the Spaniards, using his European military knowledge to fight them.
His case is considered by many a clear betrayal of the Spanish Crown because he renounced his origins and actively fought against the Spanish army, becoming an enemy of the Crown while attempting to remain loyal to his new family, the personal bonds he had established, and the new way of life he had assumed among the Maya.
Francisco de Carvajal (1470–1548)
During the rebellions in Peru, he joined Gonzalo Pizarro against the orders of Charles I of Spain.
The conflict arose over the New Laws, which limited the power of Spanish settlers in the Americas.
Carvajal participated in the fight against the forces sent by the king to enforce those rules.
His treason consists of having militarily confronted the royal army to maintain the control and privileges of the Spaniards in the Americas who controlled land and indigenous labor.
Lope de Aguirre (1510–1561)
During an authorized expedition to search for El Dorado (1560–1561), he rebelled against Spanish authority, participated in the murder of his commander, and took control of the group. Later, he abandoned the mission and declared himself in rebellion against the Crown.
He even wrote a letter to Philip II proclaiming himself his enemy.
His treason is clear: he took up arms against the king and attempted to act outside the power of the Spanish Crown, openly challenging its authority.
Antonio Pérez (1540–1611)
As secretary to Philip II, he was involved in the assassination of Juan de Escobedo (1578) due to political intrigue.
After falling from grace, he fled to Aragon and then to France and England, where he revealed confidential information about the Spanish government and published writings that directly attacked the monarchy, providing arguments to its enemies. These texts contributed to the so-called Black Legend, a collection of stories and propaganda disseminated in Europe that presented Spain as an especially cruel, fanatical, and oppressive power.
His treason consists of having provided damaging information and accounts to rival powers.
Francisco de Sandoval y Rojas (1553–1625)
He was the main confidant of Philip III and controlled much of the government between 1598 and 1618. He took advantage of his position to enrich himself systematically.
The clearest case was the relocation of the court from Madrid to Valladolid (1601–1606): he bought properties there before the move and sold them afterward at much higher prices.
Furthermore, he sold public offices and manipulated political decisions, weakening the kingdom's economy.
His treason is clear: he used power for his personal benefit instead of serving the State.
Pau Claris (1586–1641)
In 1641, during the Uprising of Catalonia, he proclaimed the Catalan Republic under the protection of France and recognized Louis XIII of France as sovereign.
This meant that he handed over political and military control of the Catalan territory to a foreign power in the midst of war, weakening the Hispanic Monarchy in the context of the Thirty Years' War.
Ferdinand VII (1784–1833)
In 1808, during the Abdications of Bayonne, he ceded the Spanish crown to Napoleon Bonaparte, which allowed for the French occupation and triggered the Peninsular War (1808–1814).
His treason did not end there: when he returned to the throne in 1814, he abolished the 1812 Constitution of Cádiz and persecuted, imprisoned, or executed the liberals who had fought against the French in his name.
In other words, he handed the country over to the invader and then punished those who defended it.
