Frederick of Prussia, meanwhile, had been beset by Austrians, Russians, and French, and had never been able to retire to winter quarters. He had continued to blockade Schweidnitz amid frost and snow, and having reduced it, at the very first symptoms of spring he suddenly burst into Moravia, and invested Olmütz, its capital. There he had to contend with the able and cautious Marshal Daun and General Laudohn, nearly as efficient. Laudohn managed to seize three thousand waggons, bringing from Silesia supplies for Frederick; and whilst the king was in this state of destitution for food even for his army, a hundred thousand Russians, under General Fermor, were marching steadily on Berlin. They had taken Königsberg, laid waste the whole country beyond the Vistula, and then pushed on for the Oder. They had arrived before Küstrin, only a few marches from Berlin, when Frederick, leaving his brother, Prince Henry, to keep Daun and Laudohn in check before Olmütz, marched against them. A terrible battle took place on the plain of Zörndorf, near Custrin, in which neither Prussians nor Russians gave quarter, and which lasted from nine in the morning till seven at night. Twenty thousand Russians were left killed or wounded on the field, and eleven thousand Prussians. The Russians retired with reluctance, and did not wholly evacuate the Prussian territory till the end of October. But Frederick himself, long before that time, had been compelled to hurry back to the support of his brother Henry, whom Daun had driven back into Saxony. He fixed his camp at Hochkirch, near Bautzen, and close to the Bohemian lines. But a few mornings after, before daybreak, Daun and Laudohn burst into his camp by a combined movement, and threw the whole into confusion before the troops could muster. When Frederick awoke at the uproar and rushed from his tent, all around was one fearful scene of slaughter and flight. The news of this defeat of the generally victorious Prussians threw the court of Vienna into ecstacies, for they thought that Frederick was ruined; and so he might have been had Daun been as alert to follow him up as he had been successful in surprising him. But Daun was naturally slow; a very few days sufficed for Frederick to collect fresh forces around him, and he suddenly darted away into Silesia. There he raised the siege of Neisse, which was invested by another division of the Austrian army; then, falling back on Dresden, threatened by Daun, he drove him back, and, marching to Breslau, fixed there his winter quarters.