Johann Georg Robertus was born on 13 December 1752 in Schriesheim. He immigrated to Denmark (Schleswig-Holstein) where on 12 November 1760 he married Apollonia Barthold in Thorning. In 1764, the family immigrated to Russia, arriving in Balzer on 28 August 1765. They and their two daughters are recorded there on the 1767 census in Household No. 9.
- Lang, Gerhard. German Colonists of Denmark on the Volga.
- Pleve, Igor. Einwanderung in das Wolgagebiet, 1764-1767 Band 1 (Göttingen: Göttinger Arbeitskreis, 1999): 74.