Napoleon lost 570,000 men in Russia in 1812. Such unparalleled losses upset the balance of power and jeopardised the French position in central Europe. Napoleon abandoned the remnants of his army in early December 1812, passed through Mainz incognito, and arrived in Paris, which only two months previously had witnessed the attempted coup by General Malet. Having expelled the invader, Tsar Alexander followed the prompting of the Freiherr vom Stein and other Germans in his entourage who urged that the Russian army continue westwards. As it did so, the Prussian contingent in the Grande Armée defected. Its commander, General Yorck, signed a convention with the Russians at Tauroggen on 30 December 1812, an action disowned by Frederick William III. The Austrian corps managed to extricate itself from Russia intact. Vienna declared its neutrality, a position it maintained even after Prussia signed the Treaty of Kalisch with Russia (26 February 1813) and declared war on France (17 March). Napoleon ordered new levees and rebuilt his forces, which he led to victory at Lützen (2 May) and Bautzen (20–1 May). These engagements proved indecisive, not least because the French lacked cavalry to exploit them. There followed the Armistice of Pleschwitz (4 June), which both sides welcomed as a breathing space. Metternich, Austria's foreign minister, now entered centre stage. He had no intention of seeing French hegemony replaced by Russia's, and hoped for the preservation of Napoleonic rule in the Rhineland.