 The Principality continued under the rule of Prince Charles through the Napoleonic era, but was mediatised by Austria in December 1813, at the insistence of King Frederick William III of Prussia, who was angered that Isenburg had raised a regiment for French service by recruiting Prussian deserters and vagabonds.Isenburg was one of only three original member princes of the Empire to be mediatized at the end of the Napoleonic era (the others being Leyen and prince-primate Dalberg).This decision was confirmed at the Congress of Vienna.