Köpenick (Slavonic Kopanica) is a historic town and locality (Ortsteil) that is situated at the confluence of the rivers Dahme and Spree in the south-east of the German capital city of Berlin. It was formerly known as Copanic and then Cöpenick, only officially adopting the current spelling in 1931. It is known for the famous imposter Hauptmann von Köpenick.
Prior to its incorporation into Berlin in 1920, Köpenick was an independent town. It then became a borough of Berlin, with an area of , making it Berlin's largest borough. In Berlin's 2001 administrative reform, the borough of Köpenick was merged with that of Treptow to create the current borough of Treptow-Köpenick.
Köpenick had a long history as an independent town. Its first known mentioning as a stronghold dates back to a 1209 deed issued by Margrave Conrad II of Lusatia, then under the name Copanic (from Old Slavic: Kopanica). It is therefore considered "older" than Berlin-Cölln, which was first mentioned in a 1237 deed. For the most part of Köpenick's history, the town was known as Cöpenick.
The former Slavic castle from about 800 was conquered by the Ascanian margraves John I and Otto III of Brandenburg in 1245, defeating their rivals Margrave Henry III of Meissen and the Archbishop of Magdeburg territory.
In 1631, during the Thirty Years' War, the emissaries of George William, Elector of Brandenburg met at Köpenick - then some distance outside Berlin - with the approaching army of Gustav Adolph, King of Sweden, in a vain effort to stop the ongoing devastation of Brandenburg.
In 1906, a shoemaker called Wilhelm Voigt masqueraded as a Prussian officer and took over the town hall of Köpenick. Carl Zuckmayer perpetuated the incident in his play The Captain of Köpenick, the model for several films and television shows.
Under the terms of the Greater Berlin Act of 1920, Köpenick became a borough of Berlin, with an area of , making it Berlin's largest borough. Besides the locality of Köpenick, the former borough included the localities of Oberschöneweide, Grünau, Schmöckwitz, Müggelheim, Rahnsdorf and Friedrichshagen. In 1931, the current name was officially adopted.
During the Cold War, Köpenick was part of East Berlin. In Berlin's 2001 administrative reform, the borough of Köpenick was merged with that of Treptow to create the current borough of Treptow-Köpenick.
Until 2002 a large radio facility for MW and FM was located near the Uhlenhorst neighbourhood, including a self-radiating radio mast, which was insulated against earth. The FM services of this facility were moved to the Fernsehturm at Alexanderplatz and the AM transmitters were moved to a new aerial mast at Zehlendorf bei Oranienburg.