Hitler was incensed by this counterthrust but quickly cancelled his order for the invasion. Then, in a wild gamble that France and Great Britain would not meet their treaty obligations to Poland, and knowing he had nothing to fear from the Soviet army, Hitler ordered his troops to strike east into Poland on September 1, 1939. Two days later, on September 3, France and Great Britain declared war on Germany. World War II had begun. And less than two years after that, Hitler scrapped his pact with Stalin and sent some 3 million Nazi soldiers pouring into the Soviet Union on June 22, 1941.
German nationalism became the sole focus of the German Question which was the question of how Germany was going to be best unified into a nation-state. The idea of unifying all German-speakers into one state was known as the Großdeutsche Lösung ("Greater German solution") which was propagated mostly by the Austrian Empire and the German Austrians. The other option, the Kleindeutsche Lösung ("Lesser German solution") only advocated unifying the northern German states without Austria and the German Austrians was supported predominantly in the Kingdom of Prussia .  The idea of including the Austrian Empire into a German nation-state was a problem because it included many non-German ethnic groups, as well as many of the areas it ruled had never been part of Germany and did not want to become part of a German nation-state.  In 1866, the feud between Austria and Prussia finally came to a head. In the final battle of the German war ( Battle of Königgrätz ) the Prussians successfully defeated the Austrians and succeeded in creating the North German Confederation .