The four major European nations that opposed the French Empire in the Napoleonic Wars—Britain, Prussia, Russia, and Austria—started making preparations for the postwar era as they witnessed Napoleon’s power crumble in 1814. Decisions that would be confirmed by the more significant Congress of Vienna of 1814–1815 were reaffirmed by the Treaty of Chaumont of March 1814. The Concert of Europe, a series of international conferences that sought to create a peaceful balance of power in Europe, began with the Congress of Vienna.