[6] His childhood was "emotionally deprived": Philip II spent long periods abroad and, after Joanna's departure, Carlos endured a marked lack of affection.

[16] In 1556, Emperor Charles V abdicated and retired to the Monastery of Yuste in southern Spain, leaving the Spanish holdings of his empire to Philip, Carlos's father.

[31] Because of his eminence, he often attended meetings of the Council of State (which dealt with foreign affairs) and was in correspondence with his aunt Margaret, who governed the Low Countries in his father's name.

[34] Fearing for his son's life, Philip sought various remedies, consulting numerous physicians and resorting to placing the relics of Diego de Alcalá by the prince's bedside.

While Philip credited the miraculous power of the Franciscan corpse,[35] modern historians attribute the prince's recovery to either a trepanation of the skull performed by the anatomist Andreas Vesalius or the application of ointments by a Moorish doctor.

[38] Allegedly, Carlos sympathized with Flemish rebels[39] and made contacts with representatives of Count Egmont and Floris of Montmorency,[40] leaders of the revolt against Philip in the Low Countries.

Just before midnight on 17 January 1568, Philip II, in armour, and with four councillors, entered Don Carlos' bedchamber in the Alcázar of Madrid where they declared his arrest,[53] seized his papers and weapons, and nailed up the windows.

In addressing public opinion and other European courts, Philip attempted to justify Carlos's imprisonment without revealing the prince's actual transgressions or mental state.

His death was used as one of the core elements of the Spanish Black Legend in the Netherlands, which needed to justify a revolt against the king, which subsequently caused The Eighty Years' War.

[62][27] Don Carlos is also portrayed in the novel "The Spanish bridegroom" by English author Jean Plaidy, where the delusional and increasingly mad and dangerous prince forms a close relationship with his French stepmother, Elizabeth of Valois, defying all attempts by his desperate father to civilise him.

The idea of King Philip confining and murdering his own son later played a minor role in establishing the anti-Spanish Black Legend[61][27] in England, and a major one in forming it in the Netherlands, Germany and central Europe.

Schiller based his work on a novel written in 1672 by the French Abbé, César Vichard de Saint-Réal, which was also the source used by the English writer Thomas Otway for his play Don Carlos, Prince of Spain.

The story of a king jailing his own son is also the basis for the Spanish play La vida es sueño (Life Is a Dream) (1635), by Pedro Calderón de la Barca; however, this play does not explicitly refer to Don Carlos, starts with a different premise, and was likely inspired by a combination of religious reflection and Plato's cave, in the line of Spanish Neoplatonism.

Reign does hold true to the facts of brain damage, but instead of a fall, Don Carlos's head is impaled by a piece of wood from his "sex horse".

Carlos is portrayed by Joseph Cuby as a 14 year old sadist betrothed to Princess Mariella (Francesca Annis) in the TV series Sir Francis Drake (1962) episode "Visit to Spain".

He inveighed publicly against the institution, ridiculed the affected piety of the inquisitors, did all he could to expose their atrocious deeds, end even declared, that if he ever came to the crown, he would abolish the inquisition, and exterminate its agents.

The inquisitors now employed all their agents and emissaries to spread abroad the most artful insinuations against the prince; and, at length, raised such a spirit of discontent among the people, that the king was under the necessity of removing Don Carlos from court.

In short, they gained so great an ascendency over the mind of the king, who was absolutely a slave to superstition, that, shocking to relate, he sacrificed the feelings of nature to the force of bigotry, and, for fear of incurring the anger of the inquisition, gave up his only son, passing the sentence of death on him himself.

Roman like, the unfortunate young hero chose bleeding and the hot bath; when the veins of his arms and legs being opened, he expired gradually, falling a martyr to the malice of the inquisitors, and the stupid bigotry of his father.