If you want to have some information about this couple, I can tell you more. I am working to create a complete Knochenmuss / Knackmuss (one family, different speeches) family tree. Friedrich Knackmuss came from Angern - between Magdeburg and Stendal (not so far from Berlin). This is the area, where the family Knackmuss / Knochenmuss started in 1545.