From this moment the thought of attack on England, even his own warfare in the Netherlands, was subordinated in the mind of the Spanish king to the need of crushing Henry the Fourth. It was not merely that Henry's Protestantism threatened to spread heresy over the West. Catholic or Protestant, the union of France under an active and enterprising ruler would be equally fatal to Philip's designs. Once gathered round its king, France was a nearer obstacle to the reconquest of the Netherlands than ever England could be. On the other hand, the religious strife, to which Henry's accession gave a fresh life and vigour, opened wide prospects to Philip's ambition. Far from proving a check upon Spain, it seemed as if France might be turned into a Spanish dependency. While the Leaguers proclaimed the Cardinal of Bourbon king, under the name of Charles the Tenth, they recognized Philip as Protector of France. Their hope indeed lay in his aid, and their army was virtually his own. On the other hand Henry the Fourth was environed with difficulties. It was only by declaring his willingness to be "further instructed" in matters of faith, in other words by holding out hopes of his conversion, that he succeeded in retaining the moderate Catholics under his standard. His desperate bravery alone won a victory at Ivry over the forces of the League, which enabled him to again form the siege of Paris in 1590. All recognized Paris as the turning-point in the struggle, and the League called loudly for Philip's aid. To give it was to break the work which Parma was doing in the Netherlands, and to allow the United Provinces a breathing space in their sorest need. But even the Netherlands were of less moment than the loss of France; and Philip's orders forced Parma to march to the relief of Paris. The work was done with a skill which proved the Duke to be a master in the art of war. The siege of Paris was raised; the efforts of Henry to bring the Spaniards to an engagement were foiled; and it was only when the king's army broke up from sheer weariness that Parma withdrew unharmed to the north. [Sidenote: England and Henry.]