The king made a general review of his troops at Aschaffenburg. After his junction with Gustavus Horn, Banner, and Duke William of Weimar, they amounted to nearly 40,000 men. His progress through Franconia was uninterrupted; for Tilly, far too weak to encounter an enemy so superior in numbers, had retreated, by rapid marches, towards the Danube. Bohemia and Bavaria were now equally near to the king, and, uncertain whither his victorious course might be directed, Maximilian could form no immediate resolution. The choice of the king, and the fate of both provinces, now depended on the road that should be left open to Count Tilly. It was dangerous, during the approach of so formidable an enemy, to leave Bavaria undefended, in order to protect Austria; still more dangerous, by receiving Tilly into Bavaria, to draw thither the enemy also, and to render it the seat of a destructive war. The cares of the sovereign finally overcame the scruples of the statesman, and Tilly received orders, at all hazards, to cover the frontiers of Bavaria with his army. Nuremberg received with triumphant joy the protector of the Protestant religion and German freedom, and the enthusiasm of the citizens expressed itself on his arrival in loud transports of admiration and joy. Even Gustavus could not contain his astonishment, to see himself in this city, which was the very centre of Germany, where he had never expected to be able to penetrate. The noble appearance of his person, completed the impression produced by his glorious exploits, and the condescension with which he received the congratulations of this free city won all hearts. He now confirmed the alliance he had concluded with it on the shores of the Baltic, and excited the citizens to zealous activity and fraternal unity against the common enemy. After a short stay in Nuremberg, he followed his army to the Danube, and appeared unexpectedly before the frontier town of Donauwerth. A numerous Bavarian garrison defended the place; and their commander, Rodolph Maximilian, Duke of Saxe Lauenburg, showed at first a resolute determination to defend it till the arrival of Tilly. But the vigour with which Gustavus Adolphus prosecuted the siege, soon compelled him to take measures for a speedy and secure retreat, which amidst a tremendous fire from the Swedish artillery he successfully executed.