The Prussian king Friedrich Wilhelm III, influenced by his wife Queen Louise and the war party in Berlin, had made the decision in August to go to war independently of any other great power, save the distant Russia.

Another course of action might have involved openly declaring war the previous year and joining Austria and Russia in the Third Coalition.

In fact, the Tsar had visited the Prussian king and queen at the tomb of Frederick the Great in Potsdam that very autumn, and the monarchs had secretly sworn to make common cause against Napoleon.

Had Prussian forces been engaged against the French in 1805, this might have contained Napoleon and prevented the eventual Allied disaster at Austerlitz.

In any event, Prussia had vacillated in the face of the swift French invasion of Austria, then hastily professed neutrality once the Third Coalition was crushed.

When Prussia does eventually declare war against France on September 25, its main ally Russia still remains far away, remobilizing.

The electorate of Saxony will be Prussia's sole German ally.

Emperor Alexander had sent an envoy to seek an armistice with the French on June 19.

Napoleon had assured the envoy that the Vistula River represents the natural borders between French and Russian influence in Europe.

On that basis, the two emperors had begun peace negotiations at the town of Tilsit after meeting on an iconic raft on the River Niemen.

The very first thing Alexander said to Napoleon was probably well-calibrated: "I hate the English as much as you do."

Napoleon had reportedly replied, "Then we have already made peace."

The two emperors spend several days reviewing each other's armies, passing out medals, and frequently talking about non-political subjects.

Although the negotiations at Tilsit feature plenty of pageantry and diplomatic niceties, they are not spared from ruthless politics.

Alexander faces pressure from his brother, Duke Constantine, to make peace with Napoleon.

Given the victory he had just achieved, the French emperor offers the Russians relatively lenient terms–demanding that Russia join the Continental System, withdraw its forces from Wallachia and Moldavia, and hand over the Ionian Islands to France.

By contrast, Napoleon dictates very harsh peace terms for Prussia, despite the ceaseless exhortations of Queen Louise.

Napoleon, wiping out half of Prussian territories from the map, creates a new kingdom of eleven hundred square miles called Westphalia.

He now appoints his young brother Jérôme as the new monarch of this kingdom.

Prussia's humiliating treatment at Tilsit causes a deep and bitter antagonism that will fester as the Napoleonic Era progresses.

Moreover, Alexander's pretensions at friendship with Napoleon lead the latter to seriously misjudge the true intentions of his Russian counterpart, who will violate numerous provisions of the treaty in the next few years.

Despite these problems, Tilsit at last gives Napoleon a respite from war and allows him to return to France, which he has not seen in over three hundred days.

His arrival will be greeted with huge celebrations in Paris.