I am also researching Niehoff-Rasehorn. I don't have much and am at a loss concerning the Rasehorn line. What I have is; H. Rasehorn married Martha (sic) Niehoff around 1895, she was born about 1870 in Halberstadt, Saxony and died in Magdelburg, Saxony-Anhalt during WW II. Her parent were Wilhelm Niehoff and Luise Emma Machemehl. I know the lived in Magdelburg from 1900 on.