The work, commenced in a spirit of humour & continued in deep seriousness, contains sketches of its composer’s friends. It may be understood that these personages comment or reflect on the original theme & each one attempts a solution of the Enigma, for so the theme is called.
Since I’ve been back I have sketched a set of Variations (orkestry) on an original theme: the Variations have amused me because I’ve labeled ‘em with the nicknames of my particular friends – you are Nimrod.”
The biblical name Nimrod is a superb example of Elgar's wordplay pertaining to the covert Theme's title because it literally spells out the English translation of Ein feste Burg – A Mighty Fortress. Nimrod is described in Genesis as ‘a mighty hunter,’ laying out in the proper sequence the first two words of the missing Theme’s title – a mighty. The third word (fortress) is alluded to by the fact Nimrod was a famous builder of fortified cities – fortresses. His reputation as an architect is so well established that a famous medieval castle on the northern slope of the Golan Heights is known as Nimrod’s Fortress. Based on the connotations associated with Nimrod, it is relatively easy to cull together the title A Mighty Fortress. While Jaeger lived and worked in England, his name and heritage were ostensibly German. This further suggests the need to translate the cobbled title from English into German: Ein feste Burg. No wonder Elgar initially suspected the covert Principal Theme would soon be discovered. When he gave Hans Richter a copy of Longfellow's Hyperion shortly after the premiere, he literally gave away the answer.
A second example occurs later in that same letter to Jaeger in which Elgar explains the rationale for his Variations:
That is to say I’ve written the variations each one to represent the mood of the ‘party’ – I’ve liked to imagine the ‘party’ writing the var: him (or her) self & have written what I think they would have written – if they were asses enough to compose – it’s a quaint idea & the result is amusing to those behind the scenes & won’t affect the hearer who ‘nose nuffin’. What think you?”
The Nimrod reference is biblically refined and suggestive, but why on earth would Elgar write asses to describe the compositional prowess of his friends? A cursory explanation would be a desire to convey the stubbornness necessary to eke out and develop a musical idea. A more sophisticated approach links that pejorative to the covert Principal Theme’s title by means of wordplay. While literally known as A Mighty Fortress, Ein feste Burg was elegantly translated by the Scottish author Thomas Carlyle as A Safe Stronghold. How is the connection between his friends and Ein feste Burg conceivably betrayed by Elgar's correspondence? The initials for A Safe Stronghold are A.S.S. By calling his friends asses, Elgar made them the butt of a double-edged joke that spells out the initials of the unstated Principal Theme from a well known English translation. As for Elgar's Enigma, what could be more difficult to crack (pardon the asinine humor) than a melodic safe with a strong combination?
Yet another example of Elgar's ingenious wordplay features prominently in the original manuscript of the Enigma Variations. On the full score Elgar asked his German friend Jaeger to pencil in the word Enigma over the opening Theme. This is a superlative example of Elgar's playful use of words as the first three letters of enigma may be shuffled to spell the German word ein with the proper translation of ein conveniently furnished by the last letter in enigma. Elgar went out of his way to ensure the word Enigma stood out on the score as it was not written by his own hand, but rather by a German friend whose names, August Jaeger, are each six letters in length just like the title Enigma. By carefully placing Enigma in a foreign script over the opening measures of the score, Elgar's hints at the foreign origin of the unstated Principal Theme, and the presence of a 6 by 6 checkerboard cipher within the Theme. This ingenious cipher is Elgar's mysterious 'dark saying' mentioned in the original 1899 program note. What better way to suggest where to hunt for the solution than to have a person whose name literally means 'hunter' write in the final piece of the puzzle directly over the opening measures of the Enigma Theme?
It is remarkable four letters from enigma share corresponding initials from the covert Principal Theme's title: A Mighty Fortress is our God. These four matching letters are clustered together in the word enigma. Although the remaining two letters from enigma (e and n) do not match the remaining two initials from the title (f and o), it is profoundly coincidental both immediately precede the correct letter in alphabetical order. That is to say e comes before f, and n before o. The title is a play on the original title, a form of counterpoint using words instead of music.
The four matching letters (a,i, m and g) may be reshuffled to spell gaim, the phonetic equivalent of game. When the remaining two letters from enigma (e and n) are added to gaim, it forms engaim, a phonetic version of endgame. In Elgar's era the term endgame was commonly used to describe the concluding sequence of moves in a game of chess. This association with chess is a critical insight because a chessboard is indistinguishable from a checkerboard, and Elgar employs a checkerboard cipher to encrypt his 'dark saying.' A Polybius square is also known as a Polybius checkerboard, and Elgar's music box cipher is a variant of the Polybius square. Around the year 1927 Elgar encoded the 14-letter phrase A-V-E-R-Y-O-L-D-C-Y-P-H-E-R in one of his exercise books using symbols originally devised in 1897 to create his Dorabella Cipher. The number 14 is tantalizing as there are 14 numbered variations in the Enigma Variations. The Polybius square is 'a very old cipher' Elgar studied carefully in an 1896 issue of The Pall Mall Gazette which featured an allegedly unbreakable box cipher by John Holt Schooling. He kept that issue of The Pall Mall Gazette in his personal library, and it is now in the possession of the Elgar Birthplace Museum. Elgar successfully decoded that supposedly insoluble cipher, a feat important enough to merit mention almost a decade later in his first biography published in 1905.
Are these examples simply the result of confirmation bias, or something more deliberate, calculated and concrete? Let the final example seal the case. On October 21, 1898 – 'Enigma' Day – Elgar first performed the Enigma Theme for his wife at the piano. In a letter written the same day he revisits his plans for his first extended symphonic work, the ‘Gordon’ Symphony:
’Gordon’ simmereth mighty pleasantly in my [brain] pan & will no doubt boil over one day.
The appearance of the word mighty in Elgar's correspondence on 'Enigma' Day is an exquisitely illuminating slip of the pen, for it hints at the fact he was dwelling on a mighty theme. In the novel Hyperion Longfellow writes, "The artist shows his character in the choice of his subject." Ein feste Burg is a heroic subject. It is also one of the most famous themes of the German School, quoted by Bach, Mendelssohn, Meyerbeer, Liszt, Raff, Wagner, and surreptitiously by Elgar. To learn more about the secrets behind the Enigma Variations, read my free eBook Elgar's Enigmas Exposed.
 Kennedy, Michael. The Life of Elgar (Musical Lives). illustrated edition ed. New York: Cambridge University Press, 2004, p. 61
 Ibid, p. 61