Though the Lutheran teaching had been accepted, great care was taken not to shock the people by any violent change. Episcopal government of the Church was retained; most of the Catholic ritual in regard to the sacraments and the Mass was adopted in the new liturgy, and even in some cases the pictures and statues were not removed from the churches. But the revolution that Gustavus had most at heart was fully accomplished. The authority of the Pope had been overthrown, and in his place the king had been accepted as the head of the Swedish Church. Nor did the Lutheran bishops find themselves in the enjoyment of greater liberty and respect as a result of their treason to the Church. Gustavus warned them that they must not carry themselves like lords, and if they would attempt to wield the sword he would know how to deal with them in a summary manner. Resenting such dictation and tyranny they began to attack Gustavus in their sermons and to organise plots for the overthrow of his government. The conspiracy was discovered (1540). Olaf and Laurence Peterson, the two prominent leaders of the reforming party, were condemned to death, but were reprieved on the payment of a large fine. Laurence was, however, removed from his position as Archbishop of Upsala. In the Diet of Vesteras in 1544 the crown of Sweden was declared to be hereditary, and was vested in the family and heirs of Gustavus. Thus the well- considered policy of Gustavus was crowned with success. By means of the Lutheran revolt he had changed the whole constitution of the country, had made himself absolute master of Sweden, and had secured the succession to the throne for his own family. But he had not broken the power of his opponents so completely as to bring peace to his country, nor, if credence be given to the proclamations in which he bewailed the increase of evil under the plea of evangelical freedom, did the reformed religion tend to the elevation of public morals. On his death in 1560 he was succeeded by his son Erik XIV. (1560-9). Hardly had the new king been proclaimed than the principle of private judgment introduced by the reformers began to produce its natural results. Calvinism, which was so opposed to Lutheranism both in doctrine and in church government, found its way into Sweden, and attracted the favourable notice of the king. Regardless for the time being of the Catholic Church, which to all appearances was dead in Sweden, the two parties, Lutherans and Calvinists, struggled for supremacy. Erik was won over to the side of the Calvinists, and measures were taken to overcome the Lutherans by force, but the king had neither the capacity nor the energy of his father. The plan miscarried; the Calvinists were defeated (1568), and Erik was deposed and imprisoned.