historian A. Chubaryan stated that no documents had been found in Russian archives that support a Soviet plan to annex Finland. Rather, the objective was to gain Finnish territory and to reinforce Soviet influence in the region. Opposing forces Soviet military plan Before the war, Soviet leadership had expected total victory within a few weeks. The Red Army had just completed the invasion of eastern Poland at a cost of fewer than 4,000 casualties after Germany attacked Poland from the west. Stalin's expectations of a quick Soviet triumph were backed up by politician Andrei Zhdanov and military strategist Kliment Voroshilov, but other generals were more reserved. Red Army Chief of Staff Boris Shaposhnikov advocated a fuller build-up, extensive fire support and logistical preparations, a rational order of battle and the deployment of the army's best units. Zhdanov's military commander, Kirill Meretskov, reported, "The terrain of coming operations is split by lakes, rivers, swamps, and is almost entirely covered by forests.... The proper use of our forces will be difficult". These doubts were not reflected in Meretskov's troop deployments, and he publicly announced that the Finnish campaign would take two weeks at most. Soviet soldiers had even been warned not to cross the border mistakenly into Sweden. The leader of the Leningrad Military District, Andrei Zhdanov, commissioned a celebratory piece from Dmitri Shostakovich, Suite on Finnish Themes, intended to be performed as the marching bands of the Red Army paraded through Helsinki. Stalin's purges in the 1930s had devastated the officer corps of the Red Army; those purged included three of its five marshals, 220 of its 264 division or higher-level commanders and 36,761 officers of all ranks. Fewer than half of all the officers remained. They were commonly replaced by soldiers who were less competent but more loyal to their superiors. Unit commanders were overseen by political commissars, whose approval was needed to approve and ratify military decisions, which they evaluated based on their political merits. The dual system further complicated the Soviet chain of command and annulled the independence of commanding officers. After the Soviet success at the Battles of Khalkhin Gol against Japan, on the USSR's eastern border, Soviet High Command had divided into two factions. One side was represented by the Spanish Civil War veterans General Pavel Rychagov from the Soviet Air Forces; the tank expert General Dmitry Pavlov and Stalin's favourite general, Marshal Grigory Kulik, the