It is not our province to analyze the motives of the Swedish King, the "Lion of the North," as he is called. How much he was actuated by ambition, how much by religion, perhaps he himself might have found it hard to say. His coming marks the turning-point of the contest; his brilliant achievements constitute the fourth period of the war. Tilly opposed him with the army of the Catholic League--Tilly, the victor of thirty desperate battles. The Emperor and his court laughed, and, thinking of the Bohemian King and the Dane, said: "Another of these snow kings has come against us. He, too, will melt in our southern sun." The Protestant princes hesitated, fearing to join Gustavus; he was hampered on every side. Tilly in his very face stormed the great Protestant city of Magdeburg, and sacked it with such merciless brutalities as raised a cry of horrified disgust, even in that age of atrocities. "Never was such a victory," wrote Tilly to the Emperor, "since the storming of Troy or of Jerusalem. I am sorry you and the ladies of the court were not there to enjoy the spectacle." A heap of blackened ruins, hiding a few hundred famished and broken outcasts, was all that remained of a splendid and prosperous city of forty thousand souls. Tilly's object in this bloody deed seems to have been to terrify the rest of Protestant Germany into submission. If so, he failed of his purpose. Gustavus promptly abandoned gentle measures, and by a threat of force compelled the Saxon elector to join him. He then met Tilly in a fierce battle near Leipsic and utterly defeated him. Tilly fled, and his army was almost annihilated, the fugitives who escaped the Swedes falling victims to the vengeance of the enraged Protestant peasantry. Few men who had taken part in the sack of Magdeburg lived long to boast of their achievement. Gustavus swept victoriously through all the Rhineland. One Catholic prince or bishop after another was defeated. The advance soon became little more than a triumphal procession, city after city opening its gates to welcome him. The Saxon army conquered Bohemia; Gustavus reached Bavaria. There on the southern bank of the River Lech the Bavarian army under Tilly and Prince Maximilian was drawn to oppose the passage of the Protestant troops. It seemed impossible to cross the broad and deep stream in the face of such a force and such a general. Gustavus kept up a tremendous cannonade for three days. He burned great fires along the shore, that the smoke might conceal his movements. Tilly was struck down by a cannon-ball, the whole Bavarian army fell into confusion, and the Swedes rushed across the river almost unopposed. Maximilian fled with his army; and Bavaria, which as yet had escaped the horrors of the war, was in its turn plundered by an enemy.