Tilsit at English => English (The Britannica Concise) Of Explained:
Agreements that France signed separately with Russia and Prussia at Tilsit, N Prussia (now Sovetsk, Russia). The treaties followed Napoleon's victories in the Napoleonic Wars and established his supremacy in Western and central Europe. France and Russia became allies and divided Europe between them, reducing Prussia and Austria to helplessness. In secret provisions, Russia joined the Continental System against British trade. By 1810 Russian trade was hampered and the czar opened Russian ports to neutral ships, causing the alliance to fail and paving the way for Napoleon's invasion of Russia in 1812.