War of the Third Coalition: The Treaty of Potsdam was signed compelling Prussia to join the coalition if it failed to negotiate peace between Russia and France.

The War of the Third Coalition was a European conflict lasting from 1805 to 1806 and was the first conflict of the Napoleonic Wars. During the war, France and its client states under Napoleon I and its ally Spain opposed an alliance, the Third Coalition, which was made up of the United Kingdom, the Austrian Empire, the Russian Empire, Naples, Sicily, and Sweden. Prussia remained neutral during the war.

The Treaty of Potsdam was a treaty signed during the War of the Third Coalition on 3 November 1805 between Alexander I of the Russian Empire and Frederick William III of Prussia. It required Prussia to mediate negotiations between Napoleon's French Empire and Russia, and if the negotiations failed, join the Third Coalition.