Fritz Reuter Literary Archive

The Fritz Reuter Literary Archive (FRLA - Fritz Reuter Literaturarchiv) in Berlin, Germany collects autographs and manuscripts by 19th century authors from Mecklenburg, Germany as well as editions of their works. The collections primarily include Fritz Reuter (1810–1874), who wrote mostly in Low German, and Ida Gräfin Hahn-Hahn (1805–1880), who wrote primarily in High German.

More information on the English and German  Wikipedia pages - including lists of some of the authors covered.