Final answer:
Otto von Bismarck united Germany through military conquest, diplomatic negotiations, and economic alliances, culminating in the proclamation of the German Empire in 1871.
Step-by-step explanation:
German unification was achieved through the efforts of Otto von Bismarck and other events that strategically expanded German power and influence. Bismarck used a combination of military conquest, diplomatic negotiations, and economic alliances to unite Germany under Prussian leadership. Through three decisive wars with Denmark, Austria, and France, Bismarck managed to exclude Austria from German affairs, assert Prussian dominance, and unite the northern German states through victory. He employed Realpolitik, a practical approach that avoided unnecessary occupation of Austria, to instead focus on German unification. The successful acquisition of territories like Alsace and Lorraine from France further solidified German unity, which was formally established in 1871 with the proclamation of the German Empire.