Collective name for the peace treaties established at Tilsit (present-day Sovetsk) between France and Russia, on July 7, 1807, and between France and Prussia on July 9, 1807.
The terms of the treaties were set by Napoleon Bonaparte and Czar Alexander I of Russia.
France's gains were considerable, if not immediately obvious as such. Prussia lost half its territory, with the ceded areas west of the Elbe river becoming part of Westphalia, and the ceded Polish areas becoming the Duchy of Warsaw (both typically Napoleonic buffer state constructs). Danzig (Gdansk) became a free city.
Russia gained the Polish areas around Bialystok, but had to recognise the French possession of the Ionian islands (the Septinsular Republic), and commit to an armistice with the Ottoman Empire.
A final secret protocol of the Russo-French treaty was the establishment of a secret alliance, chiefly aimed at Britain.