Sorry to have taken such a long time to reply... My husband's family is from Chicago. His Grandmother's maiden name was Wolff. Her father's name was Paul Theodor Wolff, b. 27 Oct 1865, Germany. He was one of 9 children born to August Wolff and Wilhelmina Bettin. In Chicago 1892, Paul Theodor Wolff married Antonia Anna Zimmerman, b. 1873, West Prussia (maybe Gollub). She was one of 5 children (3 boys - 2 girls) born to William (prob. Wilhelm) Zimmerman and Anna Schroeder. That is about all I know, as the older generations have passed away leaving no clues. It would seem possible for your Zimmerman to have married a sister to Paul Theodor Wolff. That happened a lot. I don't know names of the siblings...wish I did. It would make finding anything out a lot easier!