In 1864, Bismarck, a Prussian politician, convinces Austria to join Prussia in a war with Denmark.
Bismarck: Join Prussia in this war!
Austrians: Okay we will!
Soon after, still in 1864, the Prussians and Austrians went to war with Denmark. As a result of the war, the Prussians gained Schleswig and the Austrians gained Holstein. The war participants are celebrating their victories
Shortly after (1864), Bismarck provoked a war with Austria. This war was known as the Austro-Prussian war. The war resulted in Prussia gained Holstein, and Austria was forced to not interfere with affairs in other German states.
In 1866, Bismarck then pushed for the creation of the North German Confederation. To do so, he first needed to convince the southern German states to join. The Germans were unsure because they did not think Prussia was committed to unifying Germany.
Bismarck: Join us!
Southern Germans: Should we join?
In 1870, Bismarck changed a note sent from a French ambassador, and made it seem like they insulted the Prussian king. This caused both French and Prussia to demand war. The demand of war caused the southern Germans to join the Prussians,
Bismarck: I have the perfect plan to make the south join the Prussians!
Still in 1870, France loses the Franco-Prussian war. Because the southern germans joined the Prussians, the Prussians now declared the German Empire. The Prussian king Wilhelm I claimed the German Emperor.