The Mikado; or, The Town of Titipu is a comic opera in two acts, with music by Arthur Sullivan and libretto by W. S. Gilbert, their ninth of fourteen operatic collaborations. It opened on 14 March 1885, in London, where it ran at the Savoy Theatre for 672 performances, which was the second longest run for any work of musical theatre and one of the longest runs of any theatre piece up to that time. Before the end of 1885, it was estimated that, in Europe and America, at least 150 companies were producing the opera. The Mikado remains the most frequently performed Savoy Opera, and it is especially popular with amateur and school productions. The work has been translated into numerous languages and is one of the most frequently played musical theatre pieces in history.
Setting the opera in Japan, an exotic locale far away from Britain, allowed Gilbert to satirise British politics and institutions more freely by disguising them as Japanese. Gilbert used foreign or fictional locales in several operas, including The Mikado, Princess Ida, The Gondoliers, Utopia, Limited and The Grand Duke, to soften the impact of his pointed satire of British institutions.
The Roud Folk Song Index is a database of nearly 200,000 references to nearly 25,000 songs that have been collected from oral tradition in the English language from all over the world. It is compiled by Steve Roud, a former librarian in the London Borough of Croydon. Roud's Index is a combination of the Broadside Index (printed sources before 1900) and a "field-recording index" compiled by Roud. It subsumes all the previous well-known printed sources known to Francis James Child (the Child Ballads) and includes recordings from 1900 to 1975. Until early 2006 the index was available only by a CD subscription; it can now be found online on a website maintained by the English Folk Dance and Song Society. A partial list is also available at List of folk songs by Roud number.
The primary function of the Roud Folk Song Index is to act as a research aid which correlates versions of traditional folk song lyrics that have been independently documented over past centuries by many different collectors across both the UK and North America. It is possible by searching the database, for example by title, by first line(s), or subject matter (or a combination of any of a dozen fields) to locate each of the often numerous variants of a particular song. Comprehensive details of those songs are then available, including details of the original collected source, and a reference to where to find the text (and possibly music) of the song within a published volume in the EFDSS archive.