The original impulse came from a work of romantic fiction, the 'Dom Carlos' of St. Réal, which was first read by Schiller in the summer of 1782 and drew from him the comment that the story 'deserved the brush of a dramatist'. St. Réal's novel begins by telling how Charles the Fifth arranged, just before his abdication, that his grandson Carlos should some day marry Elizabeth of Valois: and how afterwards Philip determined to take the French princess for his own wife instead of leaving her to his son. Meanwhile, however, by much gazing at the picture of his betrothed, young Carlos had learned to love her, and she in turn had conceived for him a 'disposition to love rather than a veritable passion'. Arrived at the Spanish court the young queen wins all hearts; even the white-haired Philip falls in love with her, though he treats her with stately reserve in the presence of others and surrounds her with the restraints of Spanish etiquette. Thus the queen comes to feel that she possesses 'only the body of her husband, his soul being filled with the designs of his ambition and the meditation of his policy'. As for Carlos, his love-lorn eyes soon betray to her how it is with him, but she can only pity him, though she secretly returns his love, for she is as virtuous as she is beautiful. Not so the Princess Eboli, wife of Ruy Gomez, the tutor of Carlos. Having tried to win the love of the king and found her designs thwarted by the queen's beauty, Eboli makes advances to Prince Carlos, who lets her know that he cannot love her and thus makes her angry. In this mood she bestows her favor upon the king's half-brother, Don Juan of Austria, who is also enamored of the queen and has been watching Carlos suspiciously. Having thus made enemies of Eboli and Don Juan, Carlos next draws upon himself the hatred of the powerful Duke of Alva, of Ruy Gomez, and of the Inquisition. This he does by his outspoken criticism of their doings and his threats of punishment to be meted out to them when he shall have become king. Anxious for their own future Alva and Ruy Gomez conspire together and cause suspicions of Carlos to be whispered in the ear of the king. At first Philip is not greatly excited. When Carlos, importuned by Count Egmont, asks for a commission to the Netherlands, Philip does not refuse, but declares that he will go too and share the peril of his son. This, however, is a mere ruse to gain time. While they are waiting, the king meanwhile feigning illness, Carlos communicates freely with the queen through his bosom friend, the Marquis of Posa. Hearing of this intimacy the king now becomes really jealous, but of Posa not of Carlos. Maddened by suspicion he has the marquis murdered on the street and employs Eboli to watch the queen. After this Carlos resolves upon independent action and begins to negotiate with the Netherlanders. His operations are watched and reported by his enemies, and just as he is about to leave Spain he is arrested.