Johannes Gassmann, a farmer, his wife Magdalena, and children (Philipp Jakob, age 14; Susanna, age 13; Magdalena, age 11; Michael, age 7; Johannes, age 5) are recorded on the 1767 census of Mariental in Household No. 81. They had settled there on 15 July 1766. They are recorded there on the 1767 census in Household No. 81.
Son Michael Gassmann and his family are recorded on the 1798 census of Mariental in Household No. Mt13. Widow Susanna Gassmann Grebing is recorded on the 1798 census of Mariental in Household No. Mt30. The widow and children of [Philipp] Jakob Gassmann are recorded on the 1798 census of Mariental in Household No. Mt40.
The death of Michael Gassmann in 1826 is recorded on the 1834 census of Mariental in Household No. 26.
The 1767 census records that Johannes Gassmann came from the German village of Weissenburg in France.
- 1834 Mariental Census (Households No. 26, 183, 237).
- 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): Mt13, Mt30, Mt40.
- Pleve, Igor. Einwanderung in das Wolgagebiet, 1764-1767 Band 3 (Göttingen: Der Göttinger Arbeitskreis, 2005): 115.