The town was founded in 1699 by French Huguenots fleeing persecution in France. Though initially named Sieburg, the town was later named after Charles I, Landgrave of Hesse-Kassel, who granted them refuge. The German Huguenot Museum located here contains a picture archive, library, and family histories of the Huguenots in Germany. Charles I, Landgrave of Hesse-Kassel, had ambitious plans for town-planning and developing new water trade channels in the region; including a 'haven' in Karlshafen. Together with his engineer and architect Friedrich Conradi he developed plans for a Landgrave-Carl-Canal in order to avoid customs duty at Hannoversch M�nden, but these were never finalised. Plans for Bad Karlshafen, however, were partially completed in a baroque style by new architect Paul du Ry in 1717 and the town was renamed as Carlshaven.
Since 1977 Karlshafen has spa status, which is when it received the title 'Bad'.
Leisure and health
Bad Karlshafen is a spa town (Bad = spa), which offers a modern health centre, the Weser Therme, based on a thermal salt spring, and in 1986 a graduation tower was established
