It was about this time that a deep change came over his mind. Hitherto, although nominally attached to the communion of the ancient Church, his course of life and habits of mind had not led him to deal very earnestly with things beyond the world. The severe duties, the grave character of the cause to which his days were henceforth to be devoted, had already led him to a closer inspection of the essential attributes of Christianity. He was now enrolled for life as a soldier of the Reformation. The Reformation was henceforth his fatherland, the sphere, of his duty and his affection. The religious Reformers became his brethren, whether in France, Germany, the Netherlands, or England. Yet his mind had taken a higher flight than that of the most eminent Reformers. His goal was not a new doctrine, but religious liberty. In an age when to think was a crime, and when bigotry and a persecuting spirit characterized Romanists and Lutherans, Calvinists and Zwinglians, he had dared to announce freedom of conscience as the great object for which noble natures should strive. In an age when toleration was a vice, he had the manhood to cultivate it as a virtue. His parting advice to the Reformers of the Netherlands, when he left them for a season in the spring of 1567, was to sink all lesser differences in religious union. Those of the Augsburg Confession and those of the Calvinistic Church, in their own opinion as incapable of commingling as oil and water, were, in his judgment, capable of friendly amalgamation. He appealed eloquently to the good and influential of all parties to unite in one common cause against oppression. Even while favoring daily more and more the cause of the purified Church, and becoming daily more alive to the corruption of Rome, he was yet willing to tolerate all forms of worship, and to leave reason to combat error.