At this period, a diet was held in Ratisbon, where the complaints of the States were to be heard, measures taken for securing the repose of the Empire, and the question of peace or war finally settled. The presence of the Emperor, the majority of the Roman Catholic voices in the Electoral College, the great number of bishops, and the withdrawal of several of the Protestant votes, gave the Emperor a complete command of the deliberations of the assembly, and rendered this diet any thing but a fair representative of the opinions of the German Empire. The Protestants, with reason, considered it as a mere combination of Austria and its creatures against their party; and it seemed to them a laudable effort to interrupt its deliberations, and to dissolve the diet itself.
Banner undertook this bold enterprise. His military reputation had suffered by his last retreat from Bohemia, and it stood in need of some great exploit to restore its former lustre. Without communicating his designs to any one, in the depth of the winter of 1641, as soon as the roads and rivers were frozen, he broke up from his quarters in Lunenburg. Accompanied by Marshal Guebriant, who commanded the armies of France and Weimar, he took the route towards the Danube, through Thuringia and Vogtland, and appeared before Ratisbon, ere the Diet could be apprised of his approach. The consternation of the assembly was indescribable; and, in the first alarm, the deputies prepared for flight. The Emperor alone declared that he would not leave the town, and encouraged the rest by his example. Unfortunately for the Swedes, a thaw came on, which broke up the ice upon the Danube, so that it was no longer passable on foot, while no boats could cross it, on account of the quantities of ice which were swept down by the current. In order to perform something, and to humble the pride of the Emperor, Banner discourteously fired 500 cannon shots into the town, which, however, did little mischief. Baffled in his designs, he resolved to penetrate farther into Bavaria, and the defenceless province of Moravia, where a rich booty and comfortable quarters awaited his troops. Guebriant, however, began to fear that the purpose of the Swedes was to draw the army of Bernard away from the Rhine, and to cut off its communication with France, till it should be either entirely won over, or incapacitated from acting independently. He therefore separated from Banner to return to the Maine; and the latter was exposed to the whole force of the Imperialists, which had been secretly drawn together between Ratisbon and Ingoldstadt, and was on its march against him. It was now time to think of a rapid retreat, which, having to be effected in the face of an army superior in cavalry, and betwixt woods and rivers, through a country entirely hostile, appeared almost impracticable. He hastily retired towards the Forest, intending to penetrate through Bohemia into Saxony; but he was obliged to sacrifice three regiments at Neuburg. These with a truly Spartan courage, defended themselves for four days behind an old wall, and gained time for Banner to escape. He retreated by Egra to Annaberg; Piccolomini took a shorter route in pursuit, by Schlakenwald; and Banner succeeded, only by a single half hour, in clearing the Pass of Prisnitz, and saving his whole army from the Imperialists. At Zwickau he was again joined by Guebriant; and both generals directed their march towards Halberstadt, after in vain attempting to defend the Saal, and to prevent the passage of the Imperialists.
Banner, at length, terminated his career at Halberstadt, in May 1641, a victim to vexation and disappointment. He sustained with great renown, though with varying success, the reputation of the Swedish arms in Germany, and by a train of victories showed himself worthy of his great master in the art of war. He was fertile in expedients, which he planned with secrecy, and executed with boldness; cautious in the midst of dangers, greater in adversity than in prosperity, and never more formidable than when upon the brink of destruction. But the virtues of the hero were united with all the railings and vices which a military life creates, or at least fosters. As imperious in private life as he was at the head of his army, rude as his profession, and proud as a conqueror; he oppressed the German princes no less by his haughtiness, than their country by his contributions. He consoled himself for the toils of war in voluptuousness and the pleasures of the table, in which he indulged to excess, and was thus brought to an early grave. But though as much addicted to pleasure as Alexander or Mahomet the Second, he hurried from the arms of luxury into the hardest fatigues, and placed himself in all his vigour at the head of his army, at the very moment his soldiers were murmuring at his luxurious excesses. Nearly 80,000 men fell in the numerous battles which he fought, and about 600 hostile standards and colours, which he sent to Stockholm, were the trophies of his victories. The want of this great general was soon severely felt by the Swedes, who feared, with justice, that the loss would not readily be replaced. The spirit of rebellion and insubordination, which had been overawed by the imperious demeanour of this dreaded commander, awoke upon his death. The officers, with an alarming unanimity, demanded payment of their arrears; and none of the four generals who shared the command, possessed influence enough to satisfy these demands, or to silence the malcontents. All discipline was at an end, increasing want, and the imperial citations were daily diminishing the number of the army; the troops of France and Weimar showed little zeal; those of Lunenburg forsook the Swedish colours; the Princes also of the House of Brunswick, after the death of Duke George, had formed a separate treaty with the Emperor; and at last even those of Hesse quitted them, to seek better quarters in Westphalia. The enemy profited by these calamitous divisions; and although defeated with loss in two pitched battles, succeeded in making considerable progress in Lower Saxony.
At length appeared the new Swedish generalissimo, with fresh troops and money. This was Bernard Torstensohn, a pupil of Gustavus Adolphus, and his most successful imitator, who had been his page during the Polish war. Though a martyr to the gout, and confined to a litter, he surpassed all his opponents in activity; and his enterprises had wings, while his body was held by the most frightful of fetters. Under him, the scene of war was changed, and new maxims adopted, which necessity dictated, and the issue justified. All the countries in which the contest had hitherto raged were exhausted; while the House of Austria, safe in its more distant territories, felt not the miseries of the war under which the rest of Germany groaned. Torstensohn first furnished them with this bitter experience, glutted his Swedes on the fertile produce of Austria, and carried the torch of war to the very footsteps of the imperial throne.
In Silesia, the enemy had gained considerable advantages over the Swedish general Stalhantsch, and driven him as far as Neumark. Torstensohn, who had joined the main body of the Swedes in Lunenburg, summoned him to unite with his force, and in the year 1642 hastily marched into Silesia through Brandenburg, which, under its great Elector, had begun to maintain an armed neutrality. Glogau was carried, sword in hand, without a breach, or formal approaches; the Duke Francis Albert of Lauenburg defeated and killed at Schweidnitz; and Schweidnitz itself with almost all the towns on that side of the Oder, taken. He now penetrated with irresistible violence into the interior of Moravia, where no enemy of Austria had hitherto appeared, took Olmutz, and threw Vienna itself into consternation.
But, in the mean time, Piccolomini and the Archduke Leopold had collected a superior force, which speedily drove the Swedish conquerors from Moravia, and after a fruitless attempt upon Brieg, from Silesia. Reinforced by Wrangel, the Swedes again attempted to make head against the enemy, and relieved Grossglogau; but could neither bring the Imperialists to an engagement, nor carry into effect their own views upon Bohemia. Overrunning Lusatia, they took Zittau, in presence of the enemy, and after a short stay in that country, directed their march towards the Elbe, which they passed at Torgau. Torstensohn now threatened Leipzig with a siege, and hoped to raise a large supply of provisions and contributions from that prosperous town, which for ten years had been unvisited with the scourge of war.