when was the above mentioned empire founded?
It was founded on 1 January 1871.
German Empire
The German Empire or the Imperial State of Germany, also referred to as Imperial Germany or simply Germany, was the period of the German Reich from the unification of Germany in 1871 until the November Revolution in 1918, when the German Reich changed its form of government from a monarchy to a republic.

It was founded on 1 January 1871 when the south German states, except for Austria, joined the North German Confederation and the new constitution came into force changing the name of the federal state to the German Empire and introduced the title of German Emperor for Wilhelm I, King of Prussia from the House of Hohenzollern. Berlin remained its capital, and Bismarck, Minister-President of Prussia became Chancellor, the head of government. As these events occurred, the Prussian-led North German Confederation and its southern German allies were still engaged in the Franco-Prussian War.

who was not opposed to german unification under prussian leadership before 1870 UNANSWERABLE when did this confederation take place? Hall of Mirrors at the Palace of Versailles in France. what were the problems of reorganization? It was concluded that it was both impossible and undesirable to repress the free utterance of public opinion by reactionary measures. where was the unification occurred? German Empire.
wiki:7774824
German Empire [SEP] Introduction
The German Empire or the Imperial State of Germany, also referred to as Imperial Germany or simply Germany, was the period of the German Reich from the unification of Germany in 1871 until the November Revolution in 1918, when the German Reich changed its form of government from a monarchy to a republic. It was founded on 1 January 1871 when the south German states, except for Austria, joined the North German Confederation and the new constitution came into force changing the name of the federal state to the German Empire and introduced the title of German Emperor for Wilhelm I, King of Prussia from the House of Hohenzollern.