Otto von Bismarck was appointed Prussian Minister-President by Prussian King Wilhelm I in 1862. He had risen to importance from his anti-Austrian Confederation political stance. Although he was not an ethnic nationalist, he did in fact unite the German states under one German Reich. The conflict of the Protestant northern Germany controlled by Prussia and the South and Southwest dominated by Catholic Austria and Bavaria can be said to be the main contributor towards the length of time it took for German unification.
Bismarck had several objectives in mind when he took the appointment of Minister-President of Prussia. He wanted to increase Prussian power, maintain the power of the monarch, and maintain the power of the noble Junker class. Bismarck did not want a united Germany for the same reasons that so many others did at the time. Ethnic nationalism was the main driving force amongst those calling for a unified Germany. Bismarck, however, was looking only for increased Prussian power. Had Bismarck been seeking ethnic nationalist aims he would have opted for the Grossdeutschland response to German unification. Grossdeutschland was the concept of including all Germans within a single German Reich. This would have included the German-speaking population of the Austrian Empire. However, he did not and instead chose the path of Kleindeutschland, or the lesser Germany solution.
German unification, Bismarck demanded, must not be made under the control of the Austrian Empire. To let this happen, would be to give Austria the upper hand in the united Germany and thus diminish Prussian power. Bismarck was intent on expanding Prussian power by using the nationalist aims of a unified Germany, while simultaneously denying Austria inclusion into the Reich. The first manifestation of this policy was the exclusion of Austria from the German Zollverein, the customs union allowing for free trade across much of the German-speaking lands. After allying with the Austrian Empire to defeat the Danes in the Second War of Schleswig in 1864, Prussia went to war with Austria in 1866. The war became known as the Austro-Prussian war. Bismarck had signed an alliance with the Italians and may have made an agreement with France to ensure their neutrality in the conflict. Ultimately, the Battle of Koeniggraetz where the Austrian army was defeated proved decisive. Austria rapidly sought peace after their crushing defeat at this battle.
With Austrian defeat, Bismarck was able to exclude the Austrian Empire from the creation of the North German Confederation, which was made shortly after the war in August 1866. Austrian dominance of the German nations was severely cut-back allowing for Prussian control to enter. As well as excluding Austria, the North German Confederation also excluded some other south German states such as Bavaria, Wuerttemberg, and Baden.
The last step towards German unification was the Franco-Prussian War in 1870-1871. The vacancy of the Spanish throne and the disagreement of who to place on the throne became the breaking point of an already tense relationship between France and Prussia. The Ems Dispatch, a document that showed insults between the Prussian king and the ambassador of France, heightened public calls for war both in France and in Prussia. When France declared war on Prussia on the 19th of July 1870 it soon found that the southern German states of Bavaria, Baden, and Wuerttemberg, which were not included into the North German Confederation, had joined Prussia’s side. The Franco-Prussian War was immensely important as a step towards a unified German because it was the final push for many Germans into believing that German unification would ensure the security of all the German states against external enemies.
On January 18th, 1871 Wilhelm I is crowned Emperor of a united Germany in the Hall of Mirrors in Versailles, France. The German Reich now contained all of the former North German Confederation, including the areas won through the Second Schleswig War and the Austro-Prussian War, as well as Alsace-Lorraine which had newly been obtained through the defeat of France.
Bismarck was an undeniable factor in the eventual unification of Germany. Recognizing this, historians continue to argue over whether or not Bismarck had a “master plan” from the beginning to set up the series of events which unfolded or if Bismarck was simply after Prussian expansionism and was an opportunist. It is clear that Bismarck was certain of the hindrance to Prussian power that Austria represented. It was no accident that the form the German Reich took was without Austria. A long series of wars was necessary to both reduce the importance of Austria and its hold on the other German states and to convince the German states, especially those to the south, that German unification, dominated by a strong Prussia, was the only way for security.
Pflanze, Otto. Bismarck and the Development of Germany: Volume 1 The Period of Unification, 1815 – 1871. Princeton, NJ: Princeton University Press, 1990.