Family lore had my great-great-grandmother's maiden name as Rose Garten. I always cringed and shook my head, wondering if that could be true. Everyone knows there are real Rose Gartens out there, and other silly names, but still, I didn't want my ancestor to have to have suffered through that.
When I discovered her death certificate, and with her son, my great-grandfather, as informant, learned her name had been Sundberg, I smiled in relief.
Another son's birth certificate just arrived from London, and as she was the informant in this case. that narrows down any variances to clerical error, which is usually limited to spelling. Turns our her maiden name was Sandgart. A nice compromise between Sundberg and Garten.
Unfortunately, there are no records on Ancestry or FamilySearch of anyone ever having that surname. Anywhere. Anywhen. I plugged the word into Google, and it was a 1-word Googlewhack.
Sure, if I spell it Sandgaard, or Sundgart, I come up with some peeps from Denmark or Sweden, but somehow she had to meet her husband in Warsaw. I ask myself...Did the Danes ever invade Poland? Turns out, not to my knowledge, but there was a series of wars between Denmark, Sweden, Poland and Russia . Hmmmmm.
(JewishGen suggests Cantkert, which is still a null set on both Ancestry and Familysearch, but there are a handful in the Polish database. Since a Polish 'C' is pronounced 'Ts', that's actually pretty close.)