Gustavus landed in Rügen in June, 1630. He added five thousand men of the Stralsund garrison to his army, and took possession of all the islands at the mouths of the Oder. He then captured Stettin and extended his grasp right and left along the coast. He proposed to base himself on the Baltic, as Alexander had done on the Mediterranean. He took and garrisoned many seaboard towns and others lying not far inland. His army, reënforced by German allies and recruitment, soon rose to twenty-five thousand men, and he established a firm footing on the Oder, which river was an excellent line for operations into the heart of Germany. The imperial Field Marshal Conti, who had ten thousand men in his front, was unable to interfere with his operations. Garrisoning Stettin, Gustavus moved into Mecklenburg to encourage its Protestant princes, further secure his base, increase his supplies and forces, and gain active allies. He relied on collecting seventy to eighty thousand men. Count Tilly had been put in supreme command of the Imperial forces, in place of Wallenstein, against whom the Catholic princes had conceived a marked prejudice. This resulted in disbanding a large part of Wallenstein’s soldiers, who considered themselves only in his personal service, and left Ferdinand for the nonce but unimportant armies to oppose to the Swedish advance.
CAMPAIGN OF GUSTAVUS ADOLPHUS IN GERMANY, 1630–1–2
Having substantially rescued Mecklenburg from the Imperialists, Gustavus left a force to operate there and returned to Stettin, purposing to move with the main army up the Oder (Dec., 1630). The end of the year was at hand. The Imperial army in his front was in no condition for a winter campaign, either from habit, discipline, or equipment. For this very reason Gustavus moved against it, his own troops being well clad and equipped, and inured to cold. He soon drove the enemy back to the line of the Warta, and then sat down in an entrenched camp at Bärwalde till he could recruit his army up to a standard equal to larger operations. The Protestant Elector of Brandenburg meanly refused his help to the cause, but Catholic France subsidized the king, and the Protestants called an assembly at Leipsic to agree on new measures of defence.
Tilly now appeared on the scene, thirty-four thousand strong. The king had but twenty-five thousand men and would not risk a battle, neither would Tilly assault the Bärwalde camp. But Gustavus had a better scheme in his head. He planned to draw Tilly into Mecklenburg, and then quickly return and capture the enemy’s line on the Warta. He made forced marches into that province, fell on the Imperialists and again defeated them. Tilly, alarmed, followed with twenty-four thousand men. Gustavus, by occupying the direct road, had compelled Tilly to resort to a long circuit. When Tilly was fairly on the way, Gustavus moved rapidly and secretly back to Stettin, advanced on Frankfort, took it after a seventeen days’ siege, and thus broke up the enemy’s line. The Warta fully protected his left flank in advancing into Germany. Gustavus had completely baffled his adversary. But Tilly took bitter revenge by the capture of Magdeburg, which, though it cannot perhaps be charged to Tilly himself, was given up to sack, and suffered a horrible fate at the hands of his unbridled soldiery. Gustavus had been unable to cross neutral Brandenburg to its assistance.
The barbarous treatment of Magdeburg enraged instead of disheartening the Protestants. Two able allies, Hesse Cassel and Saxony, joined the king’s train. And by able manœuvring, restless energy, and clear-headed method he swept Pomerania and Mecklenburg of Imperial troops.
The pusillanimous conduct of the Elector of Brandenburg, under the plea of neutrality, finally constrained Gustavus to dictate terms to him. He marched on Berlin and compelled the Elector to allow free passage to the Swedes over his territory, as well as to refrain from damaging the Protestant cause, if he would not help it.
Thus in one year from his landing in Germany, Gustavus had occupied Pomerania and Mecklenburg, and had neutralized Brandenburg (June, 1631). By holding the lines of the Havel, the Spree, and the Oder, he controlled all the territory to the confines of Poland and Silesia, and with a sufficiency of reënforcements he could safely advance on central Germany.
Tilly invaded Hesse Cassel. Gustavus tried a diversion to lure him away from his new ally. Count Pappenheim opposed him at the Elbe. Gustavus stole a clever march on him, crossed and went into an entrenched camp near Werben. These entrenched camps, it will be perceived, were a feature of this period which Gustavus still affected. They continued in use until he himself in part, and Frederick wholly, demonstrated that entrenchments could be taken by vigorous assault. At this time it was considered the height of foolhardiness to attack entrenchments.
Tilly vacated Hesse Cassel and moved on the Swedish camp. Gustavus had but ten thousand men there; Tilly had twenty-seven thousand; but the king waylaid Tilly’s isolated cavalry, handled it roughly, and returned safely to camp. Tilly, despite his excess of force, did not care to risk an assault. Large reënforcements soon reached both armies. Gustavus’ diversion had accomplished all he sought. By defending the line of the Elbe and Havel, he prevented Tilly from making any compromising advance.