Czar Paul was assassinated in 1801 and was replaced by Alexander I who refused to implement the Continental System after 1806; neither had he made peace with France after the Battle of Austerlitz. The Russian army was still in Poland, and the Czar would have come to the aid of Prussia but for Prussia's collapse after the Battle of Jena. Napoleon now set out to overthrow the last great continental Power capable of withstanding his will. Marching into Prussian Poland, he tried to gain the support of the people by hinting that he was about to reconstruct their country which had disappeared in the Partitions of 1772, 1793 and 1795.

However, the difficulties of campaigning in Poland were greater than any he had ever encountered. The vast plain was so thinly populated that he could procure no foodstuffs for his men or forage for his horses; at that season snows and frosts alternated with thaws and rains which turned the whole country side into a sea of sticky mud. Napoleon attacked the Russians at Eylau in February 1807; but after a battle in which 30,000 men lost their lives, neither side could claim much advantage. After this setback Napoleon went into winter quarters.

Even though he was seven hundred miles from Paris Napoleon supervised the details of home government, directed the military occupation of Prussia, developed the Confederation of the Rhine, kept in check the hostility of Austria and Spain, and organised reinforcements and supplies for his army from all the countries which he dominated. Meanwhile the Czar was building up another coalition. By the Convention of Bartenstein of April 1807, Russia, Prussia and Sweden undertook to make no separate peace with Napoleon; Britain afterwards joined in with a promise of subsidies and a fleet to be sent to the Baltic. This combination shared the fate of its predecessors. As soon as summer made the movement of troops again possible, Napoleon fought the Russian army at the Battle of Friedland in June and destroyed it.

The Czar took a serious view of this defeat even though

• his vast resources were barely tapped;
• Swedish and Prussian forces were on the march;
• British support was on its way;
• Austria was on the point of joining the Coalition.

Alexander was filled with admiration for Napoleon and he was angry that the British Government would not guarantee him a loan. Bonaparte had never aimed at conquering Russia: his one object in the campaign was to get the Czar into the Continental System. If he could do so without having to fight any more in that difficult theatre of war, so much the better so the two emperors met at Tilsit in a pavilion erected on a raft moored in the River Niemen.

Alexander’s first words were: “I hate the English as much as you do”; to which Napoleon replied, “In that case, peace is as good as made.” During the next fortnight they met practically every day, sometimes tête-à-tête, sometimes attended by their foreign ministers. Once or twice Frederick William was allowed in, but Napoleon treated him with undisguised contempt.

There were several difficult areas in the discussions. For instance,

• Alexander - like all Czars before and since - had designs on Constantinople; but Napoleon was determined not to let Russia acquire this ancient capital of the world.
• Alexander could not altogether abandon Frederick William, to whom he had sworn eternal brotherhood a few months before; but Napoleon was determined to reduce Prussia to the rank of a second-class Power, so that it could never again interfere with his plans for dominating Germany.
• Napoleon was intent on reviving Poland in some shape or form; but Alexander feared that his own Polish subjects would be more restless than ever if there was an independent Polish state just across the frontier.
• the economic prosperity of Russia was dependent on the trade with Britain which Napoleon was determined to stop.

Napoleon used all his powers of persuasion. Alexander, dazzled by the prospect of a lion’s share in an approaching partition of Turkey, abandoned his earlier ambition to liberate western Europe from the menace of Imperial France, and fell in with Napoleon’s design that the two of them should share the domination of the world.

By the Treaty of Tilsit in July 1807, the Czar recognised the Confederation of the Rhine, now augmented by a “Kingdom of Westphalia” concocted out of Prussian territories west of the Elbe, with Jerome Bonaparte as King. Prussian Poland was formed into a Grand Duchy of Warsaw, with the Elector (henceforth "King ") of Saxony as its ruler. Russia was to observe the Berlin Decree. By secret clauses, the two emperors agreed that if Britain continued to deny the “Freedom of the Seas” they would summon Denmark, Sweden and Portugal to close their ports to British shipping, and would make war on any of the three that refused.

The actual terms of this last agreement have only recently come to light, but the gist of them was made known to the British Government by a Secret Service agent a few days after it had been signed. Cannin, who had just become Foreign Secretary, determined to be beforehand. The Baltic Powers were valuable allies, and the Danish navy would be an important addition to the fleets already at Napoleon’s disposal. He therefore proposed a defensive alliance to Denmark, promising her armed support and a handsome subsidy, provided that she sent her fleet to be interned “as a sacred pledge” in a British port for the duration of the war. He hoped that the appearance of eighty ships and 15,000 troops off Copenhagen would at once overawe the Danes and give them an excuse for submitting but he was disappointed. The Prince Regent of Denmark rejected the British proposals and only gave way after Copenhagen had been bombarded for four days and nights in September 1807. The twenty-two ships of the Danish navy were then captured and taken to Portsmouth harbour. It is doubtful, however, if Britain really gained anything in the long run. Denmark remained hostile for the rest of the war; Sweden was left defenceless and Napoleon had an excuse for labelling the British as treacherous and unscrupulous