Nazi Germany signed the Munich Agreement with Italy, Britain and France by which Czechoslovakia must cede its border regions and defenses to Nazi Germany to avoid a possible Soviet German conflict
The Union of Soviet Socialist Republics and Germany signed the Treaty of non-aggression which provided a written guarantee of peace between each party towards the other and a declared commitment that neither government would ally itself or aid an enemy of the other
The tension between the Soviets and Germany over the Balkan territories intensified and Germany began to suffer from the severe depletion of oil supply
Hitler issued directive number 21 Operation Barbarossa, a codename for an offensive war against what he perceived to be his biggest enemy of the Soviet Union
Despite continuously enhancing military and munitions by the start of the Great Patriotic War, the Soviet Union was still inferior to the German army in terms of quantity and quality of weapons and equipment
German forces were divided into three great army groups
1. Army Group North under the command of Field Marshal Wilhelm Ritter von Leeb advanced to the north with the aim of capturing Leningrad
2. Army Group Center under the command of Field Marshal Theodore von Bach with 50 divisions and two brigades in the support of Luftflotte to attack capital Moscow
3. Army Group South under the command of Field Marshal GERD von Rundstedt with 46 divisions destroyed a large part of Ukraine
The first blow took the Soviets completely by surprise when the 2nd Panzer group took Orel which was just 75 miles south of the Soviet first main defense line
Moscow's first line of defense had been shattered and over six hundred and sixty three thousand Soviet prisoners were captured bringing the tally since it started the invasion to three million
Almost from the beginning of Operation Typhoon, the weather worsened with heavy rain and accumulating snows turning the unpaved road into a glutinous mud and hampering the advance of German tanks
The German army High Command ordered a halt to the operation Typhoon so that the Germans could reorganize and resolve the increasing severe logistical problems
In over a month, along with 1,000 tanks, 11 new armies including 30 divisions of Siberian troops that were better suited in such a tough condition were deployed to assist in defending the city
The Germans intended to move the 3rd and 4th Panzer armies across the Moscow Volga canal and envelop the city from the Northeast while the 2nd Panzer group attacked Tula and then closed on Moscow from the south