The life of David D. Schroeder (1808-1877) is described on the Global Anabaptist Mennonite encyclopedia. He was the father of Maria D. Schroeder who married Abraham A. Klassen. One of their kids was my great grandfather, Heinrich A. Klassen. David D. Schroeder was also the grandfather of Aganeta Schroeder who married Heinrich Dirks. And then, one of their kids, Margarete Dirks, married my great-grandfather as his second wife.
I've always wondered where the wealth that my great grandfather and his brothers came from. It enabled them to purchase the most productive asset in South Russia, i.e. arable land. This wealth came from the Schroeders side. They, in turn, had inherited from their wealthy ancestors in Germany and were also good businessmen.