During Napoleon's retreat from Russia in 1812, Yorck independently signed the Convention of Tauroggen with Russia, breaking the Franco-Prussian alliance. Stein arrived in East Prussia and led the raising of a "Landwehr", or militia to defend the province. With Prussia's joining of the Sixth Coalition out of his hands, Frederick William III quickly began to mobilize the army, and the East Prussian "Landwehr" was duplicated in the rest of the country. In comparison to 1806, the Prussian populace, especially the middle class, was supportive of the war, and thousands of volunteers joined the army. Prussian troops under the leadership of Blücher and Gneisenau proved vital at the Battles of Leipzig (1813) and Waterloo (1815). Later staff officers were impressed with the simultaneous operations of separate groups of the Prussian Army.