What is the origin of trills in piano music ?

[ted]

A post about playing trills on Pianoworld had me thinking. Why have rapid two-note cycles, that is to say oscillations, such as trills and tremolos attained such dominance as a form of  ornamentation ? It would seem that an infinity of much more interesting rapid cycles using more than two notes is possible and certainly just as easy to play, but these are heard much more rarely (for example, the four note one at the end of Fantasie Impromptu). There would seem to be no reason I can think of. Do trills, like fugal imitation, have their origins in vocal conventions or something of that sort ?     

[Derek]

I suspect because it is simple, physically easy (arguably easier than the more than 2 note figures you mentioned, because all you need is two fingers), and extremely convenient to add almost anywhere in the playing of almost any larger figure or melody. And I suspect it may have originally come about by a combination of the above factors of ease and perhaps due to imitation of bird sounds. ::thinks of Vivaldi's Spring Concerto::

Why things like the 4 note figure that Chopin uses in Fantasy Impromptu hasn't been used much is rather mysterious to me. I think perhaps it is because nobody else used it before or after him as much as he did, and anyone who uses it thinks they are imitating Chopin if they use it.  Personally I think that's idiotic....are we being unoriginal by using trills for heaven's sake? haha