In 1863, the Danzig-based psychiatrist Karl Ludwig Kahlbaum (1828–1899) published his text on psychiatric nosology "Die Gruppierung der psychischen Krankheiten" ("The Classification of Psychiatric Diseases"). Although with the passage of time this work would prove profoundly influential, when it was published it was almost completely ignored by German academia despite the sophisticated and intelligent disease classification system which it proposed. In this book Kahlbaum categorized certain typical forms of psychosis ("vesania typica") as a single coherent type based upon their shared progressive nature which betrayed, he argued, an ongoing degenerative disease process. For Kahlbaum the disease process of "vesania typica" was distinguished by the passage of the sufferer through clearly defined disease phases: a melancholic stage; a manic stage; a confusional stage; and finally a demented stage.