Widower Robertus Gross, a miller (Müller), and his children settled in the Volga German colony of Volmer on 18 July 1766. They are recorded there on the 1767 census in Household No. 10.
The 1767 census records that Robertus Gross came from the German village of Grünstadt in the Pfalz region.
- Pleve, Igor. Einwanderung in das Wolgagebiet, 1764-1767 Band 4 (Göttingen: Göttinger Arbeitskreis, 2008): 287.