Where should this music be?

This must rank as the most heartbreaking example of premature chicken-counting in musical history. ‘Gotter has made a marvellous free adaptation of Shakespeare’s The Tempest,’ wrote poet Gottfried Bürger to the translator A.W. Schlegel on 31 October 1791. ‘Mozart is composing the piece.’ Three days later, brimming with misplaced confidence, the dramatist Friedrich Wilhelm Gotter confirmed that ‘the edifice is all ready to receive Mozart’s heavenly choruses’.

By 5 December 1791, Mozart was dead. Most probably, he never saw Gotter’s Tempest adaptation, although the musicologist Alfred Einstein stirred the pot of Mozartian myth by presuming that the master had set to work on it during his dying days. So the second most famous phantom opera drawn from the plays of Shakespeare evaporated into fantasy before it had even begun.

As for the best-known unbuilt blueprint, it has a more tangible history. Over a quarter-century, Verdi’s long-planned, never-executed opera of King Lear went through two librettists (Salvadore Cammarano and Antonio Somma), a handful of false starts, a posse of disappointed opera-house managers (starting with Benjamin Lumley in London in 1846) and numberless dark nights of the composer’s soul.