Thereafter the romance of Don Carlos unfolded rapidly. Philip had been patient and longsuffering under the affliction of such a son, but he at length despaired, and his attachment to his heir gave place to antipathy and disgust: especially when his physicians had definitely assured him that his line could never be continued by Carlos.[194] The Prince, on the other hand, hated his father bitterly, and was morose with his aunt Joan, whom he formerly loved, and with the young Austrian Princes, though he had now been formally betrothed to their sister Anna. The only person who influenced him was Isabel: ‘Il fait semblant de trouver bon tout ce que la reyne votre fille fait et dit, et n’y a personne qui dispose de lui comme elle, et c’est sans artifice ni feinte, car il ne sçait feindre ni dissimuler.’[195]
Matters came to a head at the end of the year 1567. Philip and Isabel had gone to pass Christmas at the newly commenced Palace of the Escorial, when Carlos decided to make his long contemplated attempt to escape from Spain. On the 23rd December, he whispered to his young uncle, Don Juan of Austria, that he needed his help to get horses; and Juan, recognising the seriousness of the situation, at once rode the thirty odd miles to the Escorial to tell the King. As in all his great calamities, Philip remained outwardly unmoved, and though he took such measures secretly as would frustrate the flight, he did not return to Madrid until the day previously fixed, the 17th January 1568. The next day he went with Carlos to mass; but still made no sign. In the interim, the Prince had even attempted to kill Don Juan; and it was time for his father to strike, in order to prevent some greater tragedy, for Carlos had admitted to his confessor that he had an ungovernable impulse to kill a man. Whom? asked the confessor. The King, was the reply. For once Philip broke down utterly when, with Ruy Gomez and other intimate councillors, he deliberated what should be done. Late that night, when the Prince slept, the afflicted father, with five armed gentlemen and twelve guards, obtained entrance into the chamber, in spite of secret bolts and locks; and when the Prince, disturbed, sprang up and sought for his weapons, the weapons were gone. In rage and despair, he tried to strangle himself, but was restrained; and, recognising that he was a helpless prisoner, he flung himself upon his bed in an agony of grief, and sobbed out, ‘I am not mad, not mad, only desperate.’