W. S. Gilbert presented his basic idea for a new opera to Arthur Sullivan in October 1881.
Gilbert's earliest ideas for the story of Iolanthe originated in his Bab Ballad, "The Fairy Curate": "Once a fairy / Light and airy / Married with a mortal."
The fairy marries a "prosaic" attorney and bears him a son.
After her son grows up, she visits him on Earth, but she is mistaken for his lover, since fairies perpetually appear young and beautiful.
Sullivan found the premise funny, and Gilbert set to work on fleshing out the story.
By December, he had written some lyrics for Sullivan to look at, but he struggled with the plot for several months, whereas he had dashed off earlier operas in a matter of weeks.
During these months, Sullivan took an extended trip to Egypt, Italy and elsewhere.
Upon his return to London in April 1882, he moved into a new home; in May, his beloved mother died rather suddenly.
By the end of July 1882, Gilbert had supplied Sullivan with lyrics to several of the songs, and Sullivan began work setting them to music.
Over the next two months, Sullivan met Gilbert to discuss the libretto as more lyrics were completed.
Music rehearsals began in September, and staging began in October, scheduled around performances of Gilbert and Sullivan's previous opera, Patience, which had transferred to the Savoy Theatre a year earlier.
Sullivan was still composing more numbers for the opera until 20 October, with a few modifications continuing into early November.
Uncharacteristically, Sullivan composed the overture himself, instead of assigning it to an assistant.
Two casts rehearsed simultaneously, as the opera was to open on the same night in London and New York City, a historic first for any play.

Gilbert had targeted the aristocracy and political officials for satiric treatment in earlier works.
In this opera, the House of Lords is lampooned as a bastion of the ineffective, privileged and dim-witted, whose only qualification to govern is noble birth.
The political party system, the law and other institutions also come in for a dose of satire.
Throughout Iolanthe, however, both author and composer managed to couch the criticism among such bouncy, amiable absurdities and "splendid pageantry" that it is all received as good humour, with Prime Minister Gladstone complimenting the opera's good taste.
In fact, Gilbert later refused to allow quotes from the piece to be used as part of the campaign to diminish the powers of the House of Lords.

Although titled Iolanthe all along in Gilbert's plot book, for a time the piece was advertised as Perola and rehearsed under that name.
  According to an often-repeated myth, Gilbert and Sullivan did not change the name to Iolanthe until just before the première.
In fact, however, the title was advertised as Iolanthe as early as 13 November 1882 – eleven days before the opening – so the cast had at least that much time to learn the name.
It is also clear that Sullivan's musical setting was written to match the cadence of the word "Iolanthe," and could only accommodate the word "Perola" by preceding it (awkwardly) with "O", "Come" or "Ah".
Henry Irving had produced a W. G. Wills adaptation of King René’s Daughter in London in 1880, under the name Iolanthe, and in October 1882 Gilbert asked his producer, Richard D'Oyly Carte, to request Irving's permission to use the name.
It is not known whether Irving replied.

Iolanthe premiered only three days after Patience closed at the Savoy.
The Savoy Theatre, opened only a year earlier, was a state-of-the-art facility, the first theatre in the world to be lit entirely by electricity.
Patience had transferred to the Savoy from the Opera Comique, upon the theatre's opening, but Iolanthe was the first show to premiere at the theatre.
New lighting technologies made such special effects as sparkling fairy wands possible for the first time.
The principal fairies' heads were also lit by wreaths of small illuminated stars attached to a battery.
The audience that attended the opening night in London included Captain (later Captain Sir) Eyre Massey Shaw,
W. S. Gilbert presented his basic idea for a new opera to Arthur Sullivan in October 1881. Gilbert's earliest ideas for the story of Iolanthe originated in his Bab Ballad, "The Fairy Curate": "Once a fairy / Light and airy / Married with a mortal." The fairy marries a "prosaic" attorney and bears him a son. After her son grows up, she visits him on Earth, but she is mistaken for his lover, since fairies perpetually appear young and beautiful. Sullivan found the premise funny, and Gilbert set to work on fleshing out the story. By December, he had written some lyrics for Sullivan to look at, but he struggled with the plot for several months, whereas he had dashed off earlier operas in a matter of weeks. During these months, Sullivan took an extended trip to Egypt, Italy and elsewhere. Upon his return to London in April 1882, he moved into a new home; in May, his beloved mother died rather suddenly. By the end of July 1882, Gilbert had supplied Sullivan with lyrics to several of the songs, and Sullivan began work setting them to music. Over the next two months, Sullivan met Gilbert to discuss the libretto as more lyrics were completed. Music rehearsals began in September, and staging began in October, scheduled around performances of Gilbert and Sullivan's previous opera, Patience, which had transferred to the Savoy Theatre a year earlier. Sullivan was still composing more numbers for the opera until 20 October, with a few modifications continuing into early November. Uncharacteristically, Sullivan composed the overture himself, instead of assigning it to an assistant. Two casts rehearsed simultaneously, as the opera was to open on the same night in London and New York City, a historic first for any play.
Gilbert had targeted the aristocracy and political officials for satiric treatment in earlier works. In this opera, the House of Lords is lampooned as a bastion of the ineffective, privileged and dim-witted, whose only qualification to govern is noble birth. The political party system, the law and other institutions also come in for a dose of satire. Throughout Iolanthe, however, both author and composer managed to couch the criticism among such bouncy, amiable absurdities and "splendid pageantry" that it is all received as good humour, with Prime Minister Gladstone complimenting the opera's good taste. In fact, Gilbert later refused to allow quotes from the piece to be used as part of the campaign to diminish the powers of the House of Lords.
Although titled Iolanthe all along in Gilbert's plot book, for a time the piece was advertised as Perola and rehearsed under that name.   According to an often-repeated myth, Gilbert and Sullivan did not change the name to Iolanthe until just before the première. In fact, however, the title was advertised as Iolanthe as early as 13 November 1882 – eleven days before the opening – so the cast had at least that much time to learn the name. It is also clear that Sullivan's musical setting was written to match the cadence of the word "Iolanthe," and could only accommodate the word "Perola" by preceding it (awkwardly) with "O", "Come" or "Ah". Henry Irving had produced a W. G. Wills adaptation of King René’s Daughter in London in 1880, under the name Iolanthe, and in October 1882 Gilbert asked his producer, Richard D'Oyly Carte, to request Irving's permission to use the name. It is not known whether Irving replied.
Iolanthe premiered only three days after Patience closed at the Savoy. The Savoy Theatre, opened only a year earlier, was a state-of-the-art facility, the first theatre in the world to be lit entirely by electricity. Patience had transferred to the Savoy from the Opera Comique, upon the theatre's opening, but Iolanthe was the first show to premiere at the theatre. New lighting technologies made such special effects as sparkling fairy wands possible for the first time. The principal fairies' heads were also lit by wreaths of small illuminated stars attached to a battery. The audience that attended the opening night in London included Captain (later Captain Sir) Eyre Massey Shaw,
Iolanthe