Robert Peters writes

>Stirling Newberry wrote:
>
>>ETA Hoffman whose Undine is a minor classic
>
>I am sorry but Undine is not by Hoffmann but by La Motte Fouque. ...

Doubtless others will point out to Robert that the reference is to
E.T.A.Hoffmann's through-written opera "Undine" (1816) for which La
Motte-Fouque provided a libretto based on his own verse story.

"Undine" is a fascinating oddity, and a significant work in so far as
it is the direct precursor of Weber's romantic operas, as well as those
of Marschner and Lortzing.  The libretto is good, the music quirkily
ear-catching although very much within the conventions of its time.

The same story was tackled in Lortzing's disappointingly insipid "Undine",
and by Henze; and it was also one of the sources for Dvorak's late
masterpiece "Rusalka".

Christopher Webber,  Blackheath, London,  UK.
http://www.nashwan.demon.co.uk/zarzuela.htm
"ZARZUELA!"
The Spanish Music Site