At length, in July 1468, the promising young pretender Alfonso died suddenly and mysteriously in his fifteenth year, at Cardeñosa, near Avila; perhaps of plague, as was said at the time, but more probably of poison;[10] and the whole position was at once revolutionised. Isabel had been in the Alcazar of Segovia with her friends the commander and his wife when the city was surrendered to the rebels, and from that time, late in 1567, she had followed the fortunes of Alfonso, with whom she was at his death. She at once retired broken-hearted to the convent of Santa Clara in Avila, but not, we may be certain, unmindful of the great change wrought in her prospects by her brother’s premature death. She was nearly seventeen years of age, learned and precocious far beyond her years; the events that had passed around her for the last six years had matured her naturally strong judgment, and there is no doubt from what followed that she had already decided upon her course of action. She was without such affectionate guidance as girls of her age usually enjoy; for her unhappy widowed mother, to whom she was always tender and kind, had already fallen a victim to the hereditary curse of the house of Portugal, to which she belonged, and lived thenceforward in lethargic insanity in her castle of Arevalo. Isabel’s brother the King was her enemy, and she had no other near relative: the churchmen and nobles who had risen against Henry, and were now around her, were, it must have been evident to her, greedy rogues bent really upon undermining the royal power for their own benefit; and deeply devout as Isabel was, she was quite unblinded by the illusion that the Archbishop and bishops who led the revolt were moved to their action by any considerations of morality or religion. On the other hand, the rebellious nobles and ecclesiastics could not persist in their revolt without a royal figure head. Young Alfonso, a mere child, had been an easy tool, and doubtless the leaders thought that this silent, self-possessed damsel would be quite as facile to manage.