initially at least 378,000 strong, "diminished by half during the first eight weeks of his invasion, before the major battle of the campaign. This decrease was partly due to garrisoning supply centres, but disease, desertions, and casualties sustained in various minor actions caused thousands of losses. At the Battle of Borodino on 7 September 1812—the only major engagement fought in Russia—Napoleon could muster no more than 135,000 troops and he lost at least 30,000 of them to gain a narrow and pyrrhic victory almost 600 miles inside hostile territory. The sequels were his uncontested and self-defeating occupation of Moscow and his humiliating retreat, which began on 19 October, before the first severe frosts later that month and the first snow on 5 November." Lieven cites the difficulty of finding food for troops and forage for horses in winter as an important contributing factor. Allied intervention in Russia, winter 1918–19 During the Northern Russian Expedition of the Allied intervention in the Russian Civil War, both sides, the Allied forces and the Bolshevik Red Army knew or quickly learned the principles of winter warfare and applied them whenever possible. However both sides had their resources strained and at times one side or other suffered the severe consequences of underpreparedness, but Chew concluded that winter did not provide a decisive advantage to any of the combatants. German invasion of 1941 During World War II, the Wehrmacht lacked necessary supplies, such as winter uniforms, due to the many delays in the German army's movements. At the same time, Hitler's plans for Operation Barbarossa actually miscarried before the onset of severe winter weather. Neither Hitler nor the General Staff anticipated a long campaign lasting into the winter. Thus, they failed to make adequate preparations for a possible winter campaign, such as the distribution of warm clothing and winterization of vehicles and lubricants. In fact his eastern army suffered more than 734,000 casualties (about 23% of its average strength of 3,200,000) during the first five months of the invasion before the winter started. On 27 November 1941, Eduard Wagner, the Quartermaster General of the German Army, reported that "We are at the end of our resources in both personnel and material. We are about to be confronted with the dangers of deep winter." Also of note is the fact that the unusually early winter of 1941 cut short the rasputitsa season, improving logistics in early November,