Nuremberg had exerted itself, almost beyond its power, to subsist for eleven weeks the vast crowd which was compressed within its boundaries; but its means were at length exhausted, and the king’s more numerous party was obliged to determine on a retreat. By the casualties of war and sickness, Nuremberg had lost more than 10,000 of its inhabitants, and Gustavus Adolphus nearly 20,000 of his soldiers. The fields around the city were trampled down, the villages lay in ashes, the plundered peasantry lay faint and dying on the highways; foul odours infected the air, and bad food, the exhalations from so dense a population, and so many putrifying carcasses, together with the heat of the dog-days, produced a desolating pestilence which raged among men and beasts, and long after the retreat of both armies, continued to load the country with misery and distress. Affected by the general distress, and despairing of conquering the steady determination of the Duke of Friedland, the king broke up his camp on the 8th September, leaving in Nuremberg a sufficient garrison. He advanced in full order of battle before the enemy, who remained motionless, and did not attempt in the least to harass his retreat. His route lay by the Aisch and Windsheim towards Neustadt, where he halted five days to refresh his troops, and also to be near to Nuremberg, in case the enemy should make an attempt upon the town. But Wallenstein, as exhausted as himself, had only awaited the retreat of the Swedes to commence his own. Five days afterwards, he broke up his camp at Zirndorf, and set it on fire. A hundred columns of smoke, rising from all the burning villages in the neighbourhood, announced his retreat, and showed the city the fate it had escaped. His march, which was directed on Forchheim, was marked by the most frightful ravages; but he was too far advanced to be overtaken by the king. The latter now divided his army, which the exhausted country was unable to support, and leaving one division to protect Franconia, with the other he prosecuted in person his conquests in Bavaria.
In the mean time, the imperial Bavarian army had marched into the Bishopric of Bamberg, where the Duke of Friedland a second time mustered his troops. He found this force, which so lately had amounted to 60,000 men, diminished by the sword, desertion, and disease, to about 24,000, and of these a fourth were Bavarians. Thus had the encampments before Nuremberg weakened both parties more than two great battles would have done, apparently without advancing the termination of the war, or satisfying, by any decisive result, the expectations of Europe. The king’s conquests in Bavaria, were, it is true, checked for a time by this diversion before Nuremberg, and Austria itself secured against the danger of immediate invasion; but by the retreat of the king from that city, he was again left at full liberty to make Bavaria the seat of war. Indifferent towards the fate of that country, and weary of the restraint which his union with the Elector imposed upon him, the Duke of Friedland eagerly seized the opportunity of separating from this burdensome associate, and prosecuting, with renewed earnestness, his favourite plans. Still adhering to his purpose of detaching Saxony from its Swedish alliance, he selected that country for his winter quarters, hoping by his destructive presence to force the Elector the more readily into his views.