Several of the northern states threw off the yoke of Spain and acknowledged William of Orange as their ruler, so that in a short time the Provinces of Holland and Zeeland were practically lost to Philip II. William of Orange tried to obscure the religious nature of the campaign by proclaiming religious freedom, but his followers could not be restrained. The Catholic churches were attacked, the clergy were expelled, and in 1572 nineteen priests were martyred for the faith at Gorcum. Holland and Zeeland went over completely to Calvinism, nor were the southern provinces, which were still Catholic, contented with the rule of Alva. Driven to desperation by his taxation and unconstitutional policy they formed a league with the followers of William of Orange to put an end to Spanish rule in the Netherlands. Philip II. began to realise that he had been unfortunate in his selection of a governor. A deputation that was sent from the insurgents was received kindly, and Alva's resignation of his office was accepted. In his place Don Louis Requesens was sent as governor of the Netherlands (1573-5). Though inferior to Alva in military skill he was much superior to him in the arts of diplomacy and conciliation. He withdrew promptly the financial decrees that had caused such general discontent, yielded to most of the demands made by the people, and offered a general amnesty to those who would return to their allegiance. It required all the skill of William of Orange to prevent the submission of his adherents. Disappointed by the removal of the grievances that had provoked a national uprising, he was forced to have recourse more and more to the religious issues in order to maintain his power. He proclaimed himself the protector and champion of Calvinism, and as such he could still count on the aid of the northern provinces. Unfortunately, too, at the very time when the success of his policy of mildness seemed assured, Requesens died leaving it to his successor to complete his work.