Wilhelm Gross (age 12) and his brother Nikolaus (age 8) settled in the Volga German colony of Chasselois on 2 August 1766. They are recorded there on the 1767 census along with their mother Barbara and stepfather Johannes Spiess in Household No. 22. The census records that Barbara came to Russia as a widow.
Following the destruction of Chasselois, the Spiess/Gross family relocated to the colony of Louis. In 1787, Nikolaus Gross moved from Louis to Mariental.
- 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): Mt15, Mt58, Mv1562.
- Pleve, Igor. Einwanderung in das Wolgagebiet, 1764-1767 Band 1 (Göttingen: Göttinger Arbeitskreis, 1999): 255.