The combined Imperial and Bavarian armies amounted to nearly 60,000 men, chiefly veterans. Before this force, the King of Sweden was not in a condition to keep the field. As his attempt to prevent their junction had failed, he commenced a rapid retreat into Franconia, and awaited there for some decisive movement on the part of the enemy, in order to form his own plans. The position of the combined armies between the frontiers of Saxony and Bavaria, left it for some time doubtful whether they would remove the war into the former, or endeavour to drive the Swedes from the Danube, and deliver Bavaria. Saxony had been stripped of troops by Arnheim, who was pursuing his conquests in Silesia; not without a secret design, it was generally supposed, of favouring the entrance of the Duke of Friedland into that electorate, and of thus driving the irresolute John George into peace with the Emperor. Gustavus Adolphus himself, fully persuaded that Wallenstein's views were directed against Saxony, hastily despatched a strong reinforcement to the assistance of his confederate, with the intention, as soon as circumstances would allow, of following with the main body. But the movements of Wallenstein's army soon led him to suspect that he himself was the object of attack; and the Duke's march through the Upper Palatinate, placed the matter beyond a doubt. The question now was, how to provide for his own security, and the prize was no longer his supremacy, but his very existence. His fertile genius must now supply the means, not of conquest, but of preservation. The approach of the enemy had surprised him before he had time to concentrate his troops, which were scattered all over Germany, or to summon his allies to his aid. Too weak to meet the enemy in the field, he had no choice left, but either to throw himself into Nuremberg, and run the risk of being shut up in its walls, or to sacrifice that city, and await a reinforcement under the cannon of Donauwerth. Indifferent to danger or difficulty, while he obeyed the call of humanity or honour, he chose the first without hesitation, firmly resolved to bury himself with his whole army under the ruins of Nuremberg, rather than to purchase his own safety by the sacrifice of his confederates.