Background Till 1871, Germany was divided into 38 independent states, having nothing in common except the German language. All these States were members of the German Confederation, which was weak and disunited. Between 1815 and 1848, Prince Metternich of Austria dominated the Confederation.
After 1848, Prussia became the leading State, by uniting the Confederation into an economic union (Zollverein). Austria did not join this union, thereby losing the opportunity for German leadership. In 1862, Bismarck became Chancellor of Prussia and by a series of wars, unified Germany in 1871.
The first stage in the unification of Germany started in 1848 when every German State revolted against their rulers, demanding democratic constitutions. The Frankfurt Constituent Assembly was formed, which suggested unifying Germany as a Constitutional monarchy, with the Prussian King being crowned the Emperor Germany. The Prussian King declined this offer as he did not wish his power to be limited by a Constitution.
The second phase began under Bismarck's leadership and his militaristic policy Of 'blood and iron'. He did not want Germany to be a democratic country, controlled by the revolutionaries. He wanted a Germany, dominated by the aristocracy and army under leadership of the Prussian King.
The third and final phase began with a series of wars (policy of 'blood and iron') against Austria, France and Denmark, by which Austria was removed from the German Confederation, France and Denmark defeated and King William I of Prussia was declared Emperor of a united Germany in 1871.