The first treaty of Tilsit (a small town in East Prussia, now Sovietsk in Russia) was signed in secret on July 7, 1807 by Tsar Alexander I and Emperor Napoleon I.
On June 25, 1807, the two rulers met for the first time nearby, on a boat in the middle of the Niemen.
Alexander I, having just been defeated at Friedland on June 14, 1807, wishes to gain time in the war against the French.
For his part, Napoleon, at the height of his glory, hoped to put an end to the resistance of the United Kingdom by associating Russia with the continental blockade intended to ruin the British economy.
With the treaty of July 7, it is the end of the fourth European coalition against France.
In exchange for his support for 5 years against the United Kingdom, Napoleon gave the Tsar a free hand to seize Finland at the expense of Sweden and in his plan to dismember Turkey (a clause provided for the sharing of possessions between Russia and France).
A second treaty was signed on July 9, 1807. This public treaty created the Kingdom of Westphalia to the west and the Duchy of Warsaw to the east, with the territories conquered by Napoleon from the Prussians. Danzig becomes a free city. In addition, Prussia must adhere to the continental blockade and sees its army reduced to 42,000 men.