Karl Rau and his wife are recorded on the 1775 census of Beideck in Household No. 23 along with orphan Maria Schröder (age 15). The 1775 census of Beideck does not record a relationship between the Rau and Schröder families.
Johannes Rau is recorded on the 1798 census as Johannes Roh.
- 1775 Census of Beideck (No. 23).
- Mai, Brent Alan. 1798 Census of the German Colonies along the Volga: Economy, Population, and Agriculture (Lincoln, NE: American Historical Society of Germans from Russia, 1999): Bd14, Bd74.