Beethoven's Bagatelle in A minor (WoO 59, 1810) has been a mainstay of piano lessons for generations of students. From rock and jazz to cabaret and ring tones, Für Elise is one of the best-known examples of the popularisation of classical music. If Beethoven was alive to receive royalties today, he would be a very wealthy man! But ubiquitous as the piece is, the identity of Elise herself has always remained a mystery. However, the musicologist and Beethoven expert Klaus Kopitz believes that he has at last identified her.

Elisabeth Röckel was born in 1793. She was the younger sister of the singer Joseph Röckel, who sang the role of Florestan in Beethoven's opera Fidelio and became one of the composer's closest friends. Elisabeth, too, was an accomplished pianist and singer. Kopitz asserts that she was also known by the name 'Elise' within her circle of friends, a theory backed up by an entry in the records of St Stephen's Cathedral in Vienna: at the christening of her first child, in March 1814, her name was given as 'Maria Eva Elise'.

This does indeed suggest that she was known as Elise, rather than Elisabeth, in Vienna. And as we know of no other woman of that name in Beethoven's life at the time that the piece was composed, Klaus Kopitz argues that it is to Röckel that Für Elise is dedicated. It's certainly clear from her letters that her relationship with Beethoven was a close one, as demonstrated, for example, by her account of an evening that they spent with the guitarist Mauro Giuliani and the composer Johann Hummel (who she later married).

Elisabeth recalled how Beethoven wouldn't stop teasing her, pinching her arm 'out of sheer affection'. And although it was Hummel that she ultimately chose to marry, her friendship with Beethoven continued. Elisabeth visited him in March 1827, several days before his death, and cut off a lock of his hair as a reminder of her former admirer. So how, if they were so close, could she have remained a mystery to scholars for so long? And why was Für Elise so often attributed to Therese Malfatti, to whom Beethoven proposed in 1810?

The Beethoven scholar Ludwig Nohl (1831-1885) may be to blame. When he discovered a draft of the work, he published it in 1865 with a dedication to Therese. Nohl claimed to have seen the original manuscript, saying that it had been discovered in Therese's estate, but it has not been sighted since. All that exists today is an incomplete draft of the work, on a sheet of paper that Beethoven had also apparently used to sketch out a number of other musical ideas. (The paper has since been dated to the year of his engagement.)

If, however, Für Elise really was composed for Elisabeth Röckel, it is not immediately apparent how and why the original manuscript might have fallen into Therese's hands. Kopitz admits that his theory is not particularly scientific at this point, and speculates that Therese may simply have seen the manuscript on top of Beethoven's piano and challenged her fiancé about who Elise was. Dedicating the piece to Elise would no doubt have embarrassed the composer, if it was Therese that he really wanted to marry.

Kopitz's theory will be published by the Beethoven-Haus Museum next year, and hasn't yet gained widespread acceptance. The director of the Beethoven Archive at the Museum, Bernhard Appel, has already said that he is sceptical of Klaus Kopitz' hypothesis on the grounds that Elise was a common name in Vienna at the time. In theory the dedication could refer to a woman that we don't yet know about, and to prove once and for all who Elise really was we would need to know what path the manuscript took before it was lost.