Mention has been made of the corruption that prevailed in papal affairs in the fifteenth century, and of the Italian and family interests which obscured to the Medici pope, Leo X (1513-1521), the importance of the Lutheran movement in Germany. And Leo's nephew, who became Clement VII (1523-1534), continued to act too much as an Italian prince and too little as the moral and religious leader of Catholicism in the contest which under him was joined with Zwinglians and Anglicans as well as with Lutherans. But under Paul III (1534-1549), a new policy was inaugurated, by which men were appointed to high church offices for their virtue and learning rather than for family relationship or financial gain. This policy was maintained by a series of upright and far-sighted popes during the second half of the sixteenth century, so that by the year 1600 a remarkable reformation had been gradually wrought in the papacy, among the cardinals, down through the prelates, even to the parish priests and monks. [Sidenote: The Council of Trent] The reforming zeal of individual popes was stimulated and reinforced by the work of the Council of Trent (1545-1563). The idea of effecting a "reformation in head and members" by means of a general council of the Catholic Church had been invoked several times during the century that preceded the Protestant Revolt, but, before Luther, little had been accomplished in that way. With the widening of the breach between Protestantism and the medieval Church, what had formerly been desirable now became imperative. It seemed to pious Catholics that every effort should be made to reconcile differences and to restore the unity of the Church. The errors of the manifold new theologies which now appeared might be refuted by a clear statement of Catholic doctrine, and a reformation of discipline and morals would deprive the innovators of one of their most telling weapons against the Church. It was no easy task, in that troublous time, to hold an ecumenical council. There was mutual distrust between Catholics and Protestants. There was uncertainty as to the relative powers and prerogatives of council and pope. There were bitter national rivalries, especially between Italians and Germans. There was actual warfare between the two chief Catholic families--the Habsburgs of Germany and Spain and the royal house of France.