Charles Frederic John Kielmann (my grandfather) was born in Germany in c.1829 in Wismar, Mecklenburg (in what was then Prussia), 70 or 80 miles from Kiel. There have been several variant spellings of the family name in our section of the family over the years, including Keilman ( my own name was Kielman). Charles emigrated to England as a young man (don't know when) and was a potato merchant.
My father and his father before him both had William as their second name. Possibly a link?