Wilhelm Opfer, a farmer, his wife Rosina, and his mother Anna arrived from Lübeck at the port of Oranienbaum on 4 July 1766 aboard the English frigate Love & Unity under the command of Skipper Thomas Fairfax.
They settled in the Volga German colony of Dobrinka on 20 June 1767 and are recorded there on the 1767 census in Household No. 71.
The marriage of Johann Wilhelm Opfer & Eleonore Weitzel is recorded in Büdingen on 14 March 1766. Wilhelm Opfer is recorded there as being from Belterstein which has been determined to be Beltershain located just west of Stangenrod which is from where the Weitzel family came. The 1767 census records that Wilhelm Opfer came from the German village of Belterstein in the Darmstadt region.
- 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): Db04.
- Parish records of Büdingen.
- Pleve, Igor. Einwanderung in das Wolgagebiet, 1764-1767 Band 1 (Göttingen: Göttinger Arbeitskreis, 1999): 332.
- Pleve, Igor. Lists of Colonists to Russia in 1766: Reports by Ivan Kulberg (Saratov: Saratov State Technical University, 2010): #1844.