After the end of World War I, both countries were in a state of upheaval. Germany had been defeated and was struggling to rebuild its economy and political system. Russia had undergone a revolution and was now under the control of the Bolshevik Party.
The two countries had different political ideologies and goals. Germany was a capitalist state, while Russia was a communist state. Germany was also seeking to regain its lost territory, while Russia was focused on consolidating its power and spreading communism.
Despite these differences, the two countries did cooperate in some areas. In 1922, they signed the Treaty of Rapallo, which normalized diplomatic relations and established trade agreements. They also cooperated militarily, with Germany providing training and equipment to the Red Army.
In the late 1930s, relations between the two countries began to deteriorate. Germany's annexation of Austria and the Sudetenland in 1938 alarmed the Soviet Union, which feared that Germany was becoming too powerful. The signing of the Molotov-Ribbentrop Pact in 1939, which divided Poland between the two countries, was a temporary thaw in relations, but it did not last. In 1941, Germany invaded the Soviet Union, starting World War II.
The war between Germany and the Soviet Union was one of the bloodiest conflicts in history. It resulted in the deaths of millions of people and the destruction of much of Europe. The war ended in 1945 with the defeat of Germany.