Elgar's other, dotty, enigma

It is exactly 100 years since Elgar wrote a mysterious Spanish inscription at the head of his Violin Concerto in B minor. "Aqui esta encerrada el alma de....." "Herein is enshrined the soul of....." Whose soul does it enshrine? And why?

The concerto's centenary is prompting much commemoration – it is by far the most significant British work of its genre. It's time to ask if this very Elgar-ian enigma has been satisfactorily solved. Assuming, that is, that we want it to be solved. Do we love a mystery for the sake of it, especially one attached to music that's so imbued with longing and nostalgia? Did Elgar want us to know, or did he intend to keep us guessing?

The most likely candidate for the five dots, and the one for which there appears to be most evidence, is a female friend whom Elgar nicknamed Windflower since she shared a first name – Alice – with his wife. Alice Elgar does not appear to have been perturbed by his affection for a series of younger women; it is possible that she even encouraged this, aware that the energy of these friendships or crushes provided him with a creative spur. The most significant to the Violin Concerto, his Windflower, was Alice Stuart-Wortley, daughter of the painter John Everett Millais and the wife of an MP.

By the time the Violin Concerto was commissioned by the Royal Philharmonic Society in 1909, Elgar was at the height of his powers, but he nevertheless found the process of writing the work agonising at times. During the concerto's long birth, Alice Stuart-Wortley was his confidante, egging him on when he encountered difficulties. Elgar told her that he was working on Windflower themes for the piece – the gentle, inwardly-questioning second subject of the first movement is prime amongst them.

But Alice's was not the only name with five letters. What of Elgar himself? The violin was his own instrument in his youth as a self-taught jobbing musician, working his way up from a modest background – he was the son of a piano tuner in Worcester – and hoping to achieve recognition as a composer.

Elgar, though, was no virtuoso. For the solo violin part of the concerto he enlisted the help of two consultants: first, William (Billy) Reed, leader of the London Symphony Orchestra, who worked closely on the piece with him. Then there was Fritz Kreisler, the renowned violinist who gave the concerto's official world premiere on 10 November 1910 and aided Elgar with some late alterations. Just how many people with a hand in this concerto's creation had names five letters long?

A further puzzle emerges from Pliable, author of the music blog On an Overgrown Path. He refers to the autobiography of Mrs Richard Powell, née Dora Penny, the Dorabella of Elgar's Enigma Variations, in which she states that Alice Elgar had confided that the dots referred to a wealthy American friend, Julia Worthington. Elgar described Mrs Worthington as "motherly", and it was while he and his wife were staying in her villa near Florence that he invented the opening motif of the Violin Concerto. When Pliable bought a secondhand copy of this book, a handwritten letter by Mrs Powell dropped out of it. "Having kept my promise to Lady Elgar for 40 years not to reveal the 'Secret of the 5 Dots,' I find that no one cares to know the truth," the letter read. "A writer to The Times once alluded to 'the excruciating boredom of pure fact'!"

Were Lady Elgar and Mrs Powell trying to cover the composer's tracks? For there may have been several more tracks to cover than are immediately obvious. The clue lies in the Enigma Variations themselves.

That work made Elgar's name when it was championed by the conductor Hans Richter in 1899. Each variation is a musical portrait: Elgar's wife, his publisher, friends masculine and feminine and, as grand finale, Elgar himself. The titles are games of word-association. Nimrod, a mythical hunter, refers to August Jaeger, his editor at Novello. Jaeger means hunter in German; Nimrod is a hunter. And so forth.

But the penultimate variation is headed only by three dots. It's a tender piece during which a rustle of side-drum mimics the sound of a steamer's engine, while the clarinet quotes Mendelssohn's Calm Sea and Prosperous Voyage. This variation is thought to be a tribute to Elgar's first love, Helen Weaver, a young violinist whom he had hoped to marry. Her family forbade the match, suspicious of the impecunious Elgar's prospects. The pair were heartbroken and Helen emigrated to New Zealand – a move that entailed a long sea voyage. A strong case has been built for Helen's soul as that enshrined therein.

By the time Elgar wrote the Violin Concerto, many of his friends of Enigma Variations fame were no longer alive. The Spanish quote, from the novel Gil Blas by Alain-René Lesage, is drawn from a passage in which a student reads an epitaph on a poet's tomb. Elgar's biographer Jerrold Northrop Moore suggests that behind each of the concerto's movements lay both a living inspiration and a ghost: Alice Stuart-Wortley and Helen Weaver in the first movement, Elgar's wife and his mother in the second, Billy Reed and the late Jaeger (Nimrod) in the finale.

Still, Elgar had a penchant for puzzles and he assuredly knew their worth in terms of publicity. When he placed that inscription on the Violin Concerto, he knew full well how intrigued his public would be. The fact that so many friends involved in the concerto had names of five letters might also not have escaped him.

Windflower may be both Alice Stuart-Wortley and Helen, two muses rolled into one. But also, as in the Agatha Christie murder mystery in which the crime is committed by all of the suspects together, could the five dots maybe symbolise everyone – all the five-lettered friends who provided moral support, practical advice and quasi-romantic muse-dom? Julia, Alice, Alice Elgar, Helen, Fritz, Billy and, why not, Elgar too...?

There are ample opportunities to hear the Elgar Violin Concerto in its centenary year. On the official anniversary, 10 November, Nikolaj Znaider plays it at the Barbican on the Guarneri del Gesu violin with which Kreisler gave the world premiere. An eagerly anticipated new recording by Tasmin Little is also due out in November.

But November 1910 was not quite the first time the concerto was heard. A few months earlier, at the Three Choirs Festival, Elgar and Reed presented it as work in progress, in a semi-public performance with the composer accompanying the violinist on the piano. This sneak preview in the festival so strongly associated with Elgar is being commemorated there on 10 August: the violinist Philippe Graffin will perform the concerto's original pre-Kreisler draft at Gloucester Cathedral.

Do we prefer a mystery to "the excruciating boredom of pure fact"? Of course: that's human nature, and Elgar knew it. Having planted the enigma within the piece, he could sit back and watch the fun while everyone tried to work it out. "The final 'de' leaves it indefinite as to... gender," he wrote to a friend about the famous inscription. "Now guess." We've been guessing ever since. I can't help imagining him having a good chortle about it over his pipe.

Philippe Graffin performs Elgar's Violin Concerto with the Philharmonia Orchestra, conducted by Roger Norrington, at the Three Choirs Festival (0845 652 1823) on 10 August