Johann Caspar Oberheim, son of Christoph Oberheim, was born and baptized on 3 August 1731 in Gedern. He married in Gedern on 13 October 1763 to Elisabeth Landmann, daughter of Johann Georg Landmann and widow of Johannes Müller, who had died on 12 October 1752. Caspar Oberheim and the widow Müller had had a son before they were married (Johann Christoph, born 4 September 1756, baptized 5 September 1756), and had two additional children following their marriage: (1) Johannes, born 23 July 1764 (died 29 July 1764) and (2) Carl, born 12 November 1765.
By her previous husband, Johannes Müller, Elisabeth Landmann had three children whose baptisms are recorded in the Gedern parish register: (1) Johann Christoph Müller, born 24 March 1747, baptized 26 March 1747; (2) Johann Phillip Müller, born 8 December 1748, baptized 10 December 1748; and (3) Anna Maria, born 23 July 1751, baptized 25 July 1751.
The combined Oberheim/Müller family arrived in Oranienbaum, Russia, on 4 July 1766 aboard the English frigate Love & Unity with skipper Thomas Fairfax at the helm. They settled in the Volga German colony of Reinwald on 24 June 1767 and are recorded there on the 1767 Census in Households No. 56 and 59.
- 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): Rw29.
- Pleve, Igor. Einwanderung in das Wolgagebiet, 1764-1767 Band 4 (Göttingen: Göttinger Arbeitskreis, 2008): 44 & 45.
- Pleve, Igor. Lists of Colonists to Russia in 1766 (Saratov: State Technical University, 2010): #1653.