Aegenius Mertz and his family settled in the Volga German colony of Merkel on 28 August 1766. They are recorded there on the 1767 census in Household No. 34.
In 1793, Johannes Mertz moved from Merkel to Kratzke.
- Mai, Brent Alan. 1798 Census of the German Colonies along the Volga (Lincoln, NE: American Historical Society of Germans from Russia, 1999): Kr32, Mr27, Mv1700.
- Pleve, Igor. Einwanderung in das Wolgagebiet 1764-1767 Band 3 (Goettingen: Der Göttinger Arbeitskreis; 2005): 127.