On an A-to-Z edition of The State of the Arts, it’s Edward Elgar’s Enigma… The set of variations he composed, each depicting one of his friends. But it’s no mystery who is represented in each section. It’s the elusive theme that Elgar said was not stated, but implied throughout all of the variations.

There are many theories about what the “hidden” theme is: Mozart’s “Prague” Symphony, God Save the Queen, Auld Lang Syne, even the mathematical constant pi (3.1415 rounded up to 3.142, which corresponds to the opening four notes of the theme). This would-be sleuth thinks the answer is “Ein feste Burg” (A Mighty Fortress is Our God).

Another theory ties in with the “Nimrod” variation… Elgar said that when he wrote it, he was remembering a conversation that he had had with his friend and publisher Augustus Jaeger. Elgar had been depressed with the circumstances of his life, and Jaeger sang the theme to the slow movement of Beethoven’s “Pathetique” sonata, which the opening of “Nimrod” hints at.

The other mystery that remains unsolved is the “Dorabella Cipher” – this note that Elgar wrote to his friend, Dora Penny in 1897.  Although some claim to have broken the code, the arguments are a little dubious, and impossible to prove: Elgar didn’t tell, and although he assumed Dorabella would be able to make sense of it, she never could.