Who composed the Goldberg Variations?

Bach, published in 1741 - an aria and thirty variations of extraordinary formal ingenuity, including a canon at every interval from the unison to the ninth, all built over the same bass line rather than over the tune.

The story attached to it is almost certainly false. It is said to have been written for a count with insomnia, to be played through the night by his young harpsichordist Johann Gottlieb Goldberg. The account comes from Bach's first biographer fifty years later, the dedication mentions no such commission, and Goldberg would have been about fourteen - which is not impossible and is a lot to ask.

Its modern fame is one recording. Glenn Gould's 1955 debut, played fast, dry and clipped with the ornamentation stripped back, made both the work and the pianist famous. He recorded it again in 1981 at nearly half the speed in places, a completely different reading, and died the following year - so the piece bookends a career whose owner refused to perform in public after 1964 on the grounds that concerts were a blood sport.