With the check thus inflicted, a new danger appeared above the horizon. In England there had arisen, under Cromwell, a new and powerful military state upon the ruins of the monarchy of the Stuarts. To Cromwell Spain addressed itself with the most tempting offers. The old English jealousy of France, and the political advantage of resisting its growing strength, were urged in favour of a Spanish alliance. Cromwell might renew the old glories of the Plantagenets, and might gather round him the forces of the Huguenots of the south. If Charles I. had failed at Rochelle, Cromwell might establish himself firmly at Bordeaux. [Sidenote: § 6. Spain refuses Cromwell's terms.] For a moment Cromwell was shaken. Then he made two demands of the Spanish ambassador. He must have, he said freedom for Englishmen to trade in the Indies, and permission for Englishmen carrying on commercial intercourse with Spain to profess their religion openly without interference. "To give you this," was the Spaniard's cool reply, "would be to give you my master's two eyes." [Sidenote: § 7. Alliance between France and England.] To beat down religious exclusiveness and commercial exclusiveness was the work to which Cromwell girded himself. An alliance with France was quickly made. The arrogant intolerance of Spain was to perish through its refusal to admit the new principle of toleration. The politic tolerance of France was to rise to still higher fortunes by the admission of the principle on which all its successes had been based since Richelieu's accession to power. In 1657, six thousand of Cromwell's Ironsides landed to take part in continental warfare. The union of Turenne's strategy with the valour and discipline which had broken down opposition at Naseby and Worcester was irresistible. That autumn the small Flemish port of Mardyke surrendered. In 1658 Dunkirk was taken, and given over, according to compact, to the English auxiliaries. But France, too, reaped an ample harvest. Gravelines, Oudenarde, Ypres saw the white flag of France flying from their ramparts. [Sidenote: § 8. The Treaty of the Pyrenees.] Spain was reduced to seek for peace. In 1660 the Treaty of the Pyrenees, a supplement as it were to the Treaty of Westphalia, put an end to the long war. The advantages of the peace were all on the side of France. Roussillon and Artois, with Thionville, Landrecies, and Avesnes, were incorporated with France. Another condition was pregnant with future evil. Lewis XIV. gave his hand to the sister of Philip IV. of Spain, the next heiress to the Spanish monarchy after the sickly infant who became afterwards the imbecile and childish Charles II. At her marriage she abandoned all right to the great inheritance; but even at the time there were not wanting Frenchmen of authority to point to circumstances which rendered the renunciation null and void. [Sidenote: § 9. The greatness of France based on its tolerance.]