The motive of Roumanzoff’s persistence might be open to the simple explanation that the chancellor hoped to recover power, and within a few months to re-establish his policy of antagonism to England. Alexander’s conduct could be explained by no such obvious interest. When Castlereagh’s letters of July 13 and 14 reached Cathcart at the Czar’s headquarters in Bohemia about August 10, they arrived at the most critical moment of the war. On that day the armistice expired. The next day Austria declared war on Napoleon. The combined armies of Russia, Prussia, and Austria concentrated behind the mountains, and then marched into Saxony. While starting on that campaign, August 20, the Czar was told by Lord Cathcart the reasons why his offer of mediation was rejected, and answered at once that in this case he could do nothing more.[452] Cathcart wrote to Nesselrode a formal note on the subject August 23 or 24, but did not at once communicate it,[453] because the campaign had then begun; the great battle of Dresden was fought August 26 and 27, and the allies, again beaten, retired into Bohemia August 28. The Czar saw his best military adviser Moreau killed by his side at Dresden, and he returned to Töplitz in no happy frame of mind. At Töplitz, September 1, Cathcart delivered to Nesselrode his formal note,[454] refusing Russian mediation and communicating the offer of England to negotiate directly. In an ordinary condition of government Nesselrode should have taken care that the British note should be made known without delay to the American commissioners at St. Petersburg, but the Czar kept in his own hands the correspondence with Roumanzoff and the Americans, and neither he nor Nesselrode communicated Cathcart’s act to Roumanzoff.[455] Possibly their silence was due to the new military movements. August 29 the French marshal Vandamme with forty thousand men, pursuing the allies into Bohemia, was caught between the Prussians and Austrians August 30 and crushed. During the month of September severe fighting, favorable to the allies, occurred, but no general advance was made by the allied sovereigns. Alexander next received at Töplitz toward September 20 a letter from Roumanzoff enclosing a renewal of the offer of mediation, to be proposed in a despatch to Lieven, read by Roumanzoff to the American commissioners August 24, and sent to London August 28. The Czar must have known the futility of this new step, as well as the mistake into which Roumanzoff had been led, and the awkward attitude of the American commissioners. Only a fortnight before, he had received Cathcart’s official note, and a few days earlier he had assured Cathcart that he should do no more in the matter. Yet, September 20, Alexander wrote with his own hand a note of four lines to Roumanzoff, approving his despatch to Lieven, and begging him to follow up the affair as he had begun it.[456]