Some time previously,--so early, indeed, as the 10th,--several large masses of Russians and Prussians had entered Bohemia; and on the 13th, the junction with the Austrians, which it was one of Napoleon's objects to prevent, had been accomplished. Meanwhile, he himself, being ignorant of this fact, set out on the 15th, for the bridge at Koenigstein, whence he pursued his march by Bautzen and Richenbach to Goerlitz. He reached it on the 18th, and being met there by M. de Vienne, his plenipotentiary from Prague, he had the fact communicated to him of the formal adhesion of Austria to the Grand Alliance. Though he heard, at the same time, of the reverses in Silesia, he instantly chose his part. He faced round towards Bohemia, penetrated the defiles of the mountains, spread himself over the valleys behind Gabel and Rombourg, and learned at the former of these places, that he was too late. The Grand Army of the Allies was already among the hills that border upon Saxony; and to the number of one hundred and fifty thousand men, threatened Dresden with an attack. Napoleon seems always to have calculated much on the immoveability of the enemies that opposed him. Though he knew that Schwartzenberg was within two days' march of Dresden, he flattered himself that he might still have time to strike at Blucher; and turning on his heel, he flew back to Zittau, and from thence passed without a halt to Goerlitz and Luban. In a moment, the aspect of affairs was changed. Two days' fighting served to convince the Prussians that a new spirit reigned among the troops that opposed them; and on the 23rd, the French eagles were again advanced as far as Katzbach. Here pressing instances from Dresden reached him, of the imminent danger that threatened the city, and of the total inadequacy of St. Cyr's corps to resist it; and seeing that Blucher was in full retreat, he resolved to return on his steps. Marshal Macdonald was left with seventy or eighty thousand men to keep the Prussian general in check; while with the remainder Napoleon took the road to Bautzen.