In the course of the year 1804, Russia was approached by England, and the Tsar showed a willingness to enter into an alliance for the control of Napoleon and in the interest of Europe. The mercantile differences which had kept the two nations apart were gradually adjusted, and a treaty was concluded in April, 1805. Gustavus IV of Sweden was already engaged to Russia in the same sense. Austria, too, was bound by a secret agreement with Russia (November 6th, 1804) if Napoleon made any further aggression in Italy, or threatened the integrity of Turkey. Thus by the middle of 1805 a formidable coalition was in existence. The correspondence of Talleyrand with Napoleon during that period is an amazing indication of activity. He keeps the Emperor informed of events in Turkey and Sweden, Russia and England, Prussia and Austria; he sends the news from the surgeons who are with the armies and the secret agents who are plotting and observing from Ireland to Persia; he tells the latest marriages at Paris, the dissipations of the ambassadors, the small scandals, so finely told, that will relieve Napoleon’s leisure hours.[40] There was no lack of spirit or ability in his work, but Napoleon had cast for war and it could at the most only be postponed. When Talleyrand evaded the task of writing the violent letters he directed to be sent to foreign Courts, he wrote them himself. The Prussian Ambassador informed his Court that Napoleon was forced into war in order to cover his enormous accumulation of men at Boulogne for the ostensible purpose of attacking England. The spark that lit the conflagration was Napoleon’s descent into Italy in May, 1805. Talleyrand accompanied him to Milan. On May 26th he crowned himself King of Italy with the famous iron crown of the Lombard Kings, directed that a series of splendid spectacles should impress upon the astounded nations this last stroke of the effrontery of genius. The Ligurian or Genoese Republic was at the same time declared to be incorporated in the French Empire. Austria was now bound by her agreement with Russia to take action and she began to move her forces. Talleyrand went back to Paris with Napoleon but at the close of August we find he has joined the Emperor at Boulogne. By this time all hope of invading England was over. The combined French and Spanish fleet had retreated to Cadiz. With a phrase Napoleon converted the huge army, stretching nine miles along the coast, into “the army of Germany,” wheeled it about to face Austria, and set out for Paris to make his final preparations.