There are varieties of the hamborgar all over Scandinavia, and as far as I know they have the same origin but both the tunes called "homborgar" "hamburksa" etc and the dances with the same names can vary a lot in style from region to region. And I haven't found any origin for the dance either, but it's probably just as "Hamburgian" as polska is polish (i e very little) :).

Quote from leeneia: "Yes, if a composer (say Johann Schikle) writes a piece, and I come along and change it, perhaps making it faster, slower, major or minor, or having a different number of repeats, then I might say that mine is "Something-or-Other after Johann Schikle." This shows that Johann gets the credit for the creative work, while I get credit for making it more interesting, or whatever I did."

Except that it doesn't work like this in reality :). I grew up with this tune naming tradition and it gets very confusing. Sometimes the "after X" actually means X wrote the tune. And as (I think?) you described above, sometimes Y learns and modifies the tune by X and the tune can now be referred to by Y as for example "Polska after X" and by the people who play it more in the style of Y as "Polska after Y" with no reference to X at all. Often, it was well known by all the people who knew X and Y who wrote the tune originally after all, so they just wanted to make it clear whose style they played it in.

But sometimes a tune (let's say it's that nifty little polska that X once wrote) gets traded down by so many different musicians in so many different places and with so many variations that people stop bothering with who they learned the tune from and whose style they're playing it in, because everyone knows it's the same old polska anyway, so they just pick a name from the long line and stick with that. The poor little tune may now be known to future generations as "polska after Z" even if Z just learned it from Y who learned it from X and it's been published in some collection in a transcription of Å:s or Ö:s playing (Swedish alphabet because the English one has too few letters for my example).

It's sometimes annoying with this naming tradition when you want to know more about where a tune actually came from or if you're just trying to find it and only know it as "Å:s polska" but most people call it "Polska after Z".However, it's nice to have the focus less on individual creation of tunes and more on the process of learning and adaption of tunes.