1882 Gilbert and Sullivan operetta subtitled The Peer and the Peri (8)
I believe the answer is:
iolanthe
(Other definitions for iolanthe that I've seen before include "G & S' alternative for "The Peer and the Peri"" , "G&S operetta" , "G&S piece" , "Staged work" , "one of 63 [OPERETTAS]" .)