During the period of the Slavs, who gave the city Copnic (island) its name, here where the Dahme and Spree flow together, palaces developed. In the middle of the 12th Jahrhunderts  (12th Century) it was the main palace and settlement area of the slavic clan called sprewanen ruled by their prince Jaxa von Köpenick.

In 1209 Copenic was first mentioned in documents. In 1245 the margraves Johann I. and Otto III. took the palace in posession after long struggles with the Wettin margrave von Meißen, Heinrich dem Erlauchten, as well as the  archbishop of Magdeburg, Wilbrand von Käfernburg. In 1558 it was replaced by a hunting lodge ordered by emperor Joachim II. Hektor. This caused a deficit in the treasury, and the business community profitted by it.

Prince Friedrich, heir to the throne and later Friedrich III., started the construction of today's Köpenick Palace in 1688. He convinced the Dutsch artist Rutger van Langervelt to be his architect.

In 1734, in the crest hall of  Köpenick Palace on Köpenick's Palace Island , king Friedrich Wilhelm I. of Prussia initiated the high treason trial against his son who was later to become Friedrich II. of Prussia. The Cöpenickiade of shoemaker Wilhelm Voigt (The Captain of Köpenick) makes the city internationally known on October 16, 1906. On October 1, 1920  Cöpenick becomes Berlin's 16th administrative district after the formation of Groß-Berlin. Since January 1, 1931 Köpenick is spelled with K. On June 21, 1933 the Köpenicker Blutwoche occured, hundreds of Nazi-objectors were arrested, maltreated or killed by the SA. In 2001 the districts Köpenick and Treptow merged to become Treptow-Köpenick.

Source: Wikipedia.de