area, Münsterland and Siegerland. 1594 free jurisdiction was canceled. In 1615 Herdecke became a Freiheit. In the winter of 1624/1625, Herdecke was host to a garrison of Spanish military. It was given city rights by Friedrich Wilhelm I in 1739. The Fourth Edition of Meyers Konversations-Lexikon noted in 1888: „Herdecke, town in Prussian government district Arnsberg, Hagen, 104 meters above sea levels. Lies at the navigable Ruhr and the lines Hagen-Witten, Hagen-Dahlhausen and Schwelm-Dortmund of the Prussian State Railroad Company. Has an evangelic and catholic church, great sandstone quarries as well as factories for fabrics, tobacco, leather paper and hardware, dye works and beer brewing. On the heights of the town is the Kaisberg with a tower commemorating the Baron of Stein; further away are the remnants of the Hohensyburg; the new tower was erected to honour president v. Vinke. Underneath the Hohensyburg lies the Sonnenstein, a 200 meter high plateau where every year in June the famous Rhein-Westfalic Sonnenstein fair is being held. Next to Herdecke lies Vorhalle with its iron and brass factories.“ 1939 Ende was incorporated into Herdecke. In World War II the town was godfather to the U 751, a submarine that was sunk in the Atlantic by British planes on 17 July 1942. Population history In the course of two centuries between 1739 and 1939 Herdecke changed from a medieval market town to a flourishing small town. The population between 1939 and 1993 grew at 147% because of people's wishes to "have a green home". In the 1990s the population reached its maximum to this day (26,500). The population slowly declined afterwards. Because of the population grow Herdecke is a town with the most sealed surfaces in the Government District of Arnsberg. More than a third of the town's surface has been built upon and almost 300 square metres of surface per person is sealed. Emblem The Herdecke emblem is a silvern oak on a hill bearing yellow fruit upon a red shield. The so-called "Herta-Oak" has been the city's trademark for a long time. A city seal of 1784 already shows a tree. Since the giving of the emblem by the Prussian Government in 1902, the official emblem bears a wall with three towers on the top side. Politics The current mayor of Herdecke is Katja Strauss-Köster, an independent politician endorsed by the CDU, The Greens, and FDP. She was first elected in 2009,