The vigour of the Prussians in recruiting had surprised Napoleon, but his own vigour was the marvel of Europe. In spite of the losses of the Russian campaign, he was able to take the field at the end of April with an army which at the lowest estimate was 200,000 strong. But his soldiers were for the most part mere boys, and he was sadly deficient in cavalry. The veterans of Austerlitz, of Jena, of Friedland, and of Wagram had been recklessly sacrificed on the plains of Russia. He was victorious at Lützen on May 2, was joined by the King of Saxony, entered Dresden, and thence pushed across the Elbe. On the 21st the victory of Bautzen enabled him to advance to the Oder and occupy Breslau. A renewed offer of Austrian mediation drew from him a declaration in favour of an armistice and a diplomatic congress. On June 4 an armistice was actually concluded at Poischwitz to last until August 1, and a neutral zone was provided to separate the combatants. On June 7 the demands of Austria were presented to Napoleon. They involved the renunciation by France of all territorial possessions, and even of a protectorate in Germany, and the restoration to Prussia and Austria of most of their lost provinces. Napoleon refused these terms, but accepted the mediation of Austria, and arranged for a congress which met at Prague in the middle of July. The armistice was prolonged till August 10. Both France and Austria were merely striving to gain time while they prepared for war, and there can be no doubt that the allies profited most by the delay. During the interval the news arrived of Wellington's great victory at Vitoria on June 21, and Napoleon, recalled to Mainz, occupied himself in arranging plans for the defence of the Pyrenees.