Before the era that was global warfare and such, Germany did not exist. It was made up of lesser German states that often shares the same German cultures and language. The German states were mostly referred to as in the Holy Roman Empire up until the napoleonic war.
In the napoleonic war, Napoleon spread his French relationship and military influences with the German states. Seeing this, Emperor Francois II dissolved the Holy Roman Empire. Many German states scattered across the remind of the Holy Roman Empire, losing their nationalistic identity.
It wasn’t until the late 19th century that germane nationalism arose. Otto von Bismarck, the first German chancellor, lead the German state of Prussia to unify with the rest of the German states(excluding Austria) after new political ideals of nationalism spread throughout Europe. Of course, nationalism set aflame ww1.
The alliance between Germany and Austria- Hungary is another example of German nationalism. In fact, it was the ignition of ww1 as the nationalistic Austrian detested the Serbians. After Germany’s defeat in ww1, the Germans still contained nationalistic citizens because they never experienced the defeat of Germany in the war. All they had was heard of triumph of German arms and then suddenly defeats. They believed that their efforts in the war have been sabotaged; which they blamed on the Jews.
During Hitler’s rise to power, he manipulated the German’s anger to the defeat to orchestrate a nationalistic regime, focusing on the eliminating those who were not Germans, mainly the Jewish population.
After the nazi’s defeat, Germany was split and occupied by other nations, frantically losing its nationalism. Even in the Cold War, the split that was the Eastern and western front further divided the nation. German had at last bid farewell to nationalism…at least until the future.
Hope this helped!