Iolanthe, or The Peer and the Peri is an operetta by Gilbert and Sullivan. It is the seventh of the team's fourteen operettas. It opened at the Savoy Theatre on 25 November 1882. It had a run of 398 performances. It is the first of the operettas to have its first performance at the Savoy. The story is about a group of immortal fairies who find themselves on a different side as the House of Peers. The opera makes fun of many parts of British government and law.