Orphan Hartmann Berker (age 19) settled in the Volga German colony of Jost on 5 July 1767 and is recorded there on the 1767 census in Household No. 1 along with the Johann Gottfried Jost family. The 1767 census does not record a relationship between the Berker and Jost families.
The 1767 census does not record from where Hartmann Berker came.
There are no known surviving male lines of this family among the Volga German colonies.
- Pleve, Igor. Einwanderung in das Wolgagebiet, 1764-1767 Band 2 (Göttingen: Göttinger Arbeitskreis, 2001): 195.