Are you still looking for information regarding the Rathke's?
Erdman Rathke was born 11-10-1823 and died 1895, married Regina Renata (Rabe) born 4-18-1825. They were both born in Rosenberg, Russia. They were married April 18, 1846. Their children were Jacob born 5-19-1859 married Lena Fielder, Johann Erdman (my Great, Great, Great Grand Father) born 12-3-1846, died 8-5-1907 married Adelgunda Heim, David born 10-3-1866 died 8-9-1934 married Christiana Louise Knauss,Samuel born 6-9-1870 died 9-1-1954 married Helen Michels, Renata Elizabeth (died young), Florentina Renata (died young), Friedrick died in 1916 married Elizabeth Fielder, Marie married Fred Fleishauer in Oxnard, Ca., Wilhelmina born approx 1859 married (David?) Schmidt and moved to Olpe, Kansas and John born 5-25-1861 died 1932 married Anna Marie Merker and farmed in Wichita Falls, Texas.
They first lived in Dunzig, East Prussia where he was a farmer. They returned to Rosenberg where their first two sons were born. Jacob was born 5-19-1859 and he married Lena Fiedler (who was also born in Rosenberg). Jacob farmed and died in Palmdale, California. Lena returned to South Dakota to be near her family. Her children's names were Fred, Samuel, Minnie, Lena and John (as far as I know).
In 1865 Erdman and Regina Renata moved to Kober, Crimea, Russia where David was born 10-3-1866. Samuel was born 6-8-1870. In 1874 they moved to Heilbrunn and in 1876 to Zurichthal, Russia. And then moved back to Rosenberg in 1877. From Rosenberg they took the ship Wieland from Hamburg to New York June, 19th 1877 and from there they moved to South Dakota and then on to California during the gold rush. Erdman died there at age of 72 and is buried in Palmdale, California.
After Erdman died Renata Regina moved to Olpe, Kansas with her sons John and David. She is buried at the Zion Lutheran cemetery in Olpe, Ks.
I hope this helps, if you have any questions let me know.