Which treaty in 1922 marked an important step forward for Germany and Russia?

The Rapallo Treaty, signed in 1922 between Germany and the Soviet Union, is significant as it reestablished diplomatic and economic relations between the two nations that had been severed following World War I. This treaty is pivotal because it allowed Germany to regain some degree of international legitimacy and autonomy after the punitive measures imposed by the Treaty of Versailles.

By engaging with the Soviet Union, Germany not only circumvented the isolation imposed by Western powers but also facilitated military and economic cooperation that would later bear fruit in the interwar years. This included secret military collaborations that were crucial for Germany's rearmament in violation of the Versailles Treaty. The Rapallo Treaty thus represented a strategic alliance that helped both countries in their attempts to challenge the prevailing post-WWI order in Europe.