Ironically, the work that became Purcell's best known was a variation and fugue of the Festival Rondeau he wrote for Aphra Behn's play Abdelazar (The Moor's Revenge) and is more closely connected to one of Britain's famous 20th century composers than Purcell.
In December 1945, the BBC commissioned Benjamin Britten to compose music for their documentary film Instruments of the Orchestra. The film was to be used as a teaching tool for children's music education, to give them exposure to the various instruments of the modern orchestra. It took Britten one day to decide which piece to use and two weeks for him to write the orchestration.
The piece premiered in October 1946, performed by the Liverpool Philharmonic Orchestra and was performed by the London Symphony Orchestra for the film when it was released the following month. Along with Saint-Saëns' Carnival of the Animals and Prokofiev's Peter and the Wolf it is the most performed and most well-known piece of classical music for children today.
Officially it is subtitled "Variation and Fugue on a Theme of Purcell." Everyone, of course, knows it by its more well known name: The Young Person's Guide to the Orchestra.