"Iolanthe", or "The Peer and the Peri", opened at the Savoy Theatre on November 25, 1882, three nights after the final performance of Patience at the same theatre, and ran for 398 performances.

Gilbert had taken pot shots at the aristocracy before, but in this "fairy opera," the House of Lords is lampooned as a bastion of the ineffective, privileged and dim-witted. The political party system and other institutions also come in for a dose of satire. Yet, both author and composer managed to couch the criticism among such bouncy, amiable absurdities that it is all received as good fun. 

Both Gilbert and Sullivan were at the height of their creative powers in 1882, and many people feel that Iolanthe, their seventh work together, is the most perfect of their collaborations.

Strephon, an Arcadian shepherd, wants to marry Phyllis, a Ward of Chancery. Phyllis does not know that Strephon is half fairy (his upper half — his legs are mortal!) and when she sees Strephon kissing a seemingly young woman, she assumes the worst. But her "rival" turns out to be none other than Strephon's own mother, Iolanthe, a fairy — fairies never grow old.

But Phyllis' guardian, the Lord Chancellor, and half the peers in the House of Lords are sighing after her. Soon the peers and the fairies are virtually at war, and long friendships are nearly torn asunder. But all is happily sorted out, thanks to the "subtleties of the legal mind".

(text from The Gilbert and Sullivan Archive)