My descendents were also from Alt Rudnitz, Brandenburg. My geneology is showing John (Johannes) M Lehmann born 2 Nov 1813 and married Wilhelmine Cleimmer (or Klammer?) in Alt Rudnitz. There is a book in the Beaver Dam, WI library that tells the story of a group of Germans that immigrated to Dodge Co. 1839. This group also settle in Freistadt, WI and built the Freistadt Trinity Lutheran Church (there is a grave yard attached to the church. My original descendent went to Hustisford, WI. According to the book, these German Lutherans left Germany because Kaiser Wilhelm declared the Catholic church as the state religion. Not sure if they were deposed to leave. Will have to do search on internet about political climate in Germany 1839. Also, you can contact the Pommerisch Verhein organization in Freistadt, WI to find out more about your relatives.