Johann Andreas Leonhardt, son of Johann Heinrich Leonhardt & Maria Elisabeth Pfaff, was born 13 March 1723 in Sprendlingen, at the time part of the county of Isenburg. Andreas Leonhardt married Anna Gertrude Herth on 22 April 1751 in Sprendlingen. Andreas and Anna Gertrude arrived with their children at the port in Oranienbaum on 13 September 1766. They arrived in Frank in 1767 and are recorded there on the 1767 Census in Household No. 59.
This Leonhardt line has been traced back to Johann Wilhelm Leonhardt who was born about 1605 and died in 1681 in Sprendlingen.
Separately, Heinrich Leonhardt arrived in Russia on 30 May 1766. The first settler's list states that he is also from Sprendlingen, though a matching person has not been found in the Sprendlingen records. He is not the son of Johann Andreas and Anna Gertrude according to the Sprendlingen Familienbuch.
- Knöß, Heinrich and Sehring, Ute. Familienbuch Sprendlingen, Vol. 1 and Vol. 2 (Hessische Familiengeschichtliche Vereinigung, 2013)
- Pleve, Igor. Einwanderung in das Wolgagebiet, 1764-1767 Band 1 (Göttingen: Göttinger Arbeitskreis, 1999): 423 and 428.
- Pleve, Igor. Lists of Colonists to Russia in 1766: Reports by Ivan Kulberg (Saratov: Saratov State Technical University, 2010): pp. 58 and 362.