In the same year was laid the foundations of a union which was to prove of such unbounded value to Spain; Juan II of Aragon solicited the hand of Isabella of Castile for his son and heir Don Ferdinand, king of Sicily. The overture was formally received by the princess; but obstacles of so formidable a nature intervened that, for some time, there was little hope of a successful issue to the negotiations. Neither the king nor the queen wished to see the cause of Isabella supported by so powerful a neighbour as the future monarch of Aragon would necessarily be. Besides, several barons, who had followed the fortunes of Henry, and procured great estates at the expense of the infanta’s adherents, naturally dreaded her accession in any case, especially if there should be a junction of her power with that of Aragon. [Illustration: QUEEN ISABELLA] Such, however, was the eagerness of Juan to conclude the match; such the sums he distributed among the Castilian nobles; and so powerful the interference of the archbishop of Toledo in the cause, that her adherents decided on bringing the affair as soon as possible to a conclusion. The whole negotiation was secretly conducted; the rather as the princess was sought both by the duke of Berri, brother to the French king, and by the monarch of Portugal, whose agents were sure to oppose every obstacle in their power to the union with Aragon. For a time she was a prisoner in Madrigal, where it was evidently intended to detain her until she gave her consent to either the Portuguese or the Frenchman. The former was considered too old to have issue, the latter was too far removed to be dreaded. She contrived to acquaint her friends with her unexpected position. The primate immediately collected three hundred lances, and marched to her relief; the admiral of Castile and the bishop of Curia did the same; she was released, and triumphantly escorted to Valladolid. Ferdinand was invited to hasten from Aragon with all possible expedition, while Henry was absent in Andalusia, and receive his bride. As he was likely to be intercepted on his reaching the Castilian territory, he assumed a suitable disguise, and, with three attendants only, eluded the design of his enemies. On the 25th of October, 1469, the royal pair received the nuptial benediction in the cathedral of Valladolid.