Varied repeats

What are the sources, if any, that specifically tell us that repeats should be varied, and ornamented more that the first statement, in particular in Baroque binary (dance) forms? Or, conversely, that one shouldn’t play the same thing twice? I’m aware, of course, of the French tradition of the double. But then there is no evidence that these doubles were ever meant to replace repeats, on the contrary. On the other hand, we know that François Couperin specifically requests that his music be played as it is written, with nothing more, and nothing less than what’s on the page. So this would seem to preclude any further ornaments on repeats.
Thanks.

Not to add to the confusion; but I have seen it claimed that sometimes what we take for repeat signs in early sources are only fancy double bars. (Sorry, typically, I cannot give an example off the top of my head: perhaps others can help here.)

David

This does not address Dennis’s question directly, but it’s worth remembering that Couperin himself provided versions of some of his pieces with much more extensive ornamentation (mainly in Book I, if I recall correctly). Granted that these come from the composer himself, but it does seem to indicate that the plain version of some pieces was not considered quite enough. Furthermore, he wouldn’t have complained about people changing the ornamentation in his pieces if no one was doing that, which seems to suggest a tradition of varied ornamentation in binary pieces.

Le 16/10/2020 14:59, David Perry via The Jackrail écrit :

This does not address Dennis’s question directly, but it’s worth remembering that Couperin himself provided versions of some of his pieces with much more extensive ornamentation (mainly in Book I, if I recall correctly). Granted that these come from the composer himself, but it does seem to indicate that the plain version of some pieces was not considered quite enough. Furthermore, he wouldn’t have complained about people changing the ornamentation in his pieces if no one was doing that, which seems to suggest a tradition of varied ornamentation in binary pieces.

Couperin wasn’t complaining about varied repeats, but about players who
didn’t play what he wrote (even the first time). So I’m afraid his
remarks suggest nothing of the sort. And only that he wanted his pieces
to be played with all the ornaments he wrote - no more, no less.

“Je suis toujours surpris (apres les soins que je le suis donné pour
marquer les agrémens qui conviennent à mes Pièces, dont j’ay donné, à
part, une explication assés intelligible dans une Méthode particulière,
connue sous le titre de L’art de toucher le Clavecin), d’entendre des
personnes qui les ont aprises sans s’y assujetir. C’est une négligence
qui n’est point pardonnable d’autant qu’il n’est point arbitraire d’y
mettre tels agrémens qu’on veut.Je déclare donc que mes pièces doivent
être exécutées comme je les ay marquées, et qu’elles ne feront jamais
une certaine impression sur les personnes qui ont le gout vray tant
qu’on n’observera pas à la lettre tout ce que j’y ay marqué, sans
augmentation ni diminution”

Dennis