The article investigates the hitherto little elaborated conceptual history of Wilson's hepatolenticular degeneration and Westphal's pseudosclerosis from the mid-nineteenth century up to present day, mainly in German-speaking countries. This disease exemplifies how neurological diseases have come into existence and also demonstrates how clinical descriptions of a few isolated cases merge into a nosological diagnosis, how recognized therapeutic measures are developed and how the underlying genetic causes are identified. For some time German-speaking neurologists were in disagreement about whether or not a disease described by Carl Westphal in 1883 was identical with one described by and later named after Kinnier Wilson. This article presents the publications by Adolf Strümpell, Alois Alzheimer, August Bostroem and Walther Spielmeyer as the major contributions of German-speaking specialists to a deeper understanding of an illness and investigates whether or not the two disease concepts represent identical illnesses or not. From 1970 onwards the "Morbus Wilson Center" in Leipzig became important for the development of recognized therapeutic measures and their application in medical practice in Eastern Germany (the former GDR) and its findings have been incorporated in the present Guidelines of the German Society for Neurology published in 2008 for the treatment of Wilson's disease.