September 12, 1882
To bed at 7. Up again at 11. Carte came – also F. Cellier.
Went to the theatre at 1. rehearsed 1st Act Music.
Gilbert came back with me – worked together.
Mr & Mrs Carter, F. & Mrs R. dined here.
Sullivan is knee deep in Iolanthe, though the show didn’t yet have that title. Gilbert has given Sullivan some pages, at least starting back in June, though Sullivan didn’t start composing until (probably) late July. On July 25 the two had a working session at Sullivan’s that ended in a dinner party, including one guest called “Capt: Shaw”.
They are working on the Finale of Act 1; this is a pattern of work Sullivan was still following in his last completed opera, Rose of Persia, in 1899. At first glance, it may seem counter-intuitive to begin work on a new opera with the first act’s finale. But if you need to compose, score, and rehearse a new show in four months, time management is vital. Composing the large ensemble numbers first allowed G&S to provide more music to more actors early in the rehearsal process.
This is reflected in this diary entry, “rehearsed 1st Act Music.” This is probably Iolanthe‘s first music rehearsal. Sullivan has just spent the past three weeks “taking the cure” at the lovely spa town of Bad Bertrich, in the Moselle Valley. This was one trip that included Sullivan’s Himmlische Nächte, presumably with Fanny Ronalds, though her name does not appear in the Bertrich diary entries, although Sullivan does mention leaving Victoria Station in London with “Mrs C & daughter”. Mrs C (for Carter) was Fanny’s mother.

To make it home in time for this rehearsal, Sullivan traveled all the previous day from Metz, to Brussels, to London, including the “crossing” of course; his luggage was lost for 12 hours. Hence “To bed at 7” meant 7am that morning.
Carte was of course Richard D’Oyly Carte, and Cellier was Frank Cellier. You gotta wonder why they called, when they presumably “knew” they’d soon be seeing Sullivan in the theatre that afternoon.
After rehearsal, Gilbert “came back,” to Sullivan’s home in London, and they worked some more. Dinner was a family affair including Fanny Ronalds, her parents, and her daughter ‘Fannette’.
A long day on only four hours sleep!