Johann Friedrich Ruf, a day laborer and son-in-law of Christian Benner, migrated with his wife and son from Württemberg to Denmark (Schleswig-Holstein) in 1762. In 1765, they joined the immigration to Russia.
They settled in the Volga German colony of Holstein on 2 May 1766 and are recorded there on the 1767 census in Household No. 32.
In 1788, Christoph Ruf moved from Holstein to Schwab. In 1790, Johann Adam Ruf moved from Holstein to Galka.
- Eichhorn, Alexander, Jacob & Mary Eichhorn. The Immigration of German Colonists to Denmark and Their Subsequent Emigration to Russia in the Years 1759-1766 (Deiningen, Germany: Drukerei und Verlag Steinmeier GmbH & Co. Kg, 2012): 570.
- 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): Gk34, Ho27, Sb42, Mv0900, Mv0905.