Of the three great monarchs whose fame had filled the world during the last forty years, only one remained alive, and he was engaged in a desperate struggle. Throughout the autumn and winter of 1546-47, Charles V. carried on a vigorous campaign against the coalition of Princes known as the League of Schmalkalde. Christina watched the progress of the war with keen anxiety, and saw with distress that her brother-in-law, the Palatine, had joined the rebel ranks. Frederic had never forgiven the Emperor for sacrificing his wife's rights by the Treaty of Spires, and showed his displeasure by refusing to attend the Chapter of the Golden Fleece at Utrecht in January, 1546. He further annoyed Charles by introducing Lutheran rites at Heidelberg, and on Christmas Day he and Dorothea received Communion in both kinds at the hands of a Protestant pastor in the Church of the Holy Ghost. But he still hesitated to take up arms against the friend of his youth. At length, in August, he declared himself on the Protestant side, and for the first time the red flag of the Palatinate was seen in the camp of the Emperor's foes. Before long, however, his courage failed him, and when Charles recovered the imperial city of Halle, in Suabia, Frederic hastened thither to make his peace. Tears rose to the veteran's eyes when the Emperor said how much it had grieved him to see so old a friend in the ranks of his foes, but hastened to add that he forgave him freely and would only remember his past services. From this time the Palatine's loyalty never again wavered, but he was obliged to restore Catholic rites in Heidelberg and to give up his fortress of Hoh-Königsberg in Franconia to Albert of Brandenburg.[398] The Duke of Würtemberg and the cities of Ulm and Augsburg soon followed the Palatine's example, and Charles's triumph was complete by the decisive victory of Mühlberg. "God be thanked, who never forsakes his own," wrote Granvelle to Mary of Hungary from the battle-field, at midnight on the 24th of April.[399] The Elector John Frederick of Saxony and the Landgrave of Hesse were made prisoners, the League of Schmalkalde was dissolved, and Titian commemorated the Emperor's heroic deeds in a famous equestrian portrait. [Sidenote: NOV., 1547] THE DIET OF AUGSBURG]