towards a peaceable recovery of the German Protestants. Accordingly, the Pope despatched Giovanni Morone (not yet a cardinal) as nuncio to Hagenau and Worms in 1540; and in 1541 Cardinal Gasparo Contarini took part in the adjustment proceedings at the Conference of Regensburg. It was Contarini who proposed the famous formula "by faith alone are we justified," which did not, however, supersede the Roman Catholic doctrine of good works. At Rome, this definition was rejected in the consistory of 27 May, and Luther declared that he could accept it only provided the opposers would admit that this formula constituted a change of doctrine. Yet, even after the Regensburg Conference had proved fruitless, the Emperor insisted on a still larger council, with the final result being the Council of Trent, which was finally convoked on 15 March 1545, under the bull Laetare Hierusalem. Meanwhile, after the peace of Crespy (September 1544), Emperor Charles V (1519–56) began to put down Protestantism by force. Pending the Diet of Worms in 1545, the Emperor concluded a covenant of joint action with the papal legate Cardinal Alessandro Farnese, with Paul III agreeing to aid in the projected war against the German Protestant princes and estates. This prompt acquiescence was probably grounded on personal motives: since the Emperor was preoccupied in Germany, the moment now seemed opportune for the Pope to acquire for his son Pier Luigi the duchies of Parma and Piacenza. Although these belonged to the Papal States, Paul III planned to overcome the reluctance of the cardinals by exchanging these papal duchies for the less valuable domains of Camerino and Nepi. The Emperor agreed, welcoming the prospect of 12,000 infantry, 500 cavalry, and considerable funds from the Pope. In Germany the campaign began in the west, where Archbishop of Cologne Hermann of Wied had converted to Protestantism in 1542. Emperor Charles began open warfare against the Protestant princes, estates, and cities allied in the Schmalkaldic League (see Philip of Hesse). Hermann was excommunicated on 16 April 1546, and was compelled by the Emperor to abdicate in February 1547. By the close of 1546, Charles V had subjugated South Germany. The victory at the Battle of Mühlberg, on 24 April 1547, established his imperial sovereignty everywhere in Germany, and the two leaders of the League were captured. The Emperor declared the Augsburg Interim as a magnanimous compromise with the defeated schismatics. Although the Emperor