There is a touching story of how the young librettist Arrigo Boito (right) gracefully lured the ageing Verdi out of retirement and collaborated with him on two last, great Shakespearian masterpieces - Otello and Falstaff. Yet, as usual, the reality is somewhat different. To begin with, Boito was no longer that young - 45 by the time of Otello's premiere - and his relationship with Verdi had already gone through a number of "political" ups and downs before a working rapprochement became established. Even so, it feeds the next component of the Boito myth - namely, that after collaborating with and basking in the shadow of the master, Boito tried his own hand at composition and came up with his own grand opera, Mefistofele.

Again, the reality is very different. Boito was not firstly a librettist and then a composer, but firstly a composer/librettist and then just a librettist. Boito had actually started writing his ambitious Faust opera from the time he was a student in Milan. In his early twenties, the idealistic Boito launched his massive Mefistofele on an unsuspecting audience at La Scala. The work promptly precipitated the classic operatic fiasco, and was duly withdrawn after only two performances.

Boito hid his humiliation and set about writing libretti for others, yet he returned to drastically revise Mefistofele, which subsquently received a far better reception in Bologna in 1875. Afterwards, Boito's compositional urge seems to have been drained out of him. From when he was 20, Boito had sketched a second opera on the subject of Nero, but, when he died, 56 years after its inception, Nerone still remained unfinished.

So, Boito's legacy as a composer resides with a single work - and what a strange work it is. It's almost as if Boito himself had made a Faustian pact for one great moment of glory, with the consequence that he would then subsequently be "damned" to a life of writing words for the music of others. Why were so many composers obsessed with the Faust story in the first place, as it's essentially an internal drama involving a mere trio of central participants - Faust, Margarethe and Mephistopheles?

Gounod's contemporaneous solution was to flesh out the minor parts. Boito's ambition was somewhat different, for his initial solution was to come up with a setting for more or less the whole of Goethe's massive drama, which would probably have equalled Wagner's Ring in scope. However, Boito didn't have Wagner's technique (or patience), and his revised Mefistofele brings the project far closer in line with conventional Italian opera of the time, emphasizing the relationship of Faust and Margherita and the conflict of good and evil.

Yet it was still not completely conventional, for Boito's version is perhaps the only musical telling of Faust in which the name Faust doesn't appear in the title. It's the villain of the piece whom Boito seems to be really interested in. And that's probably where the lasting virtue of his Mefistofele lies - in the star bass vehicle. And living almost as strange a life as Boito must now be the American bass Samuel Ramey who regularly plays the devil in Gounod's Faust, Berlioz's Damnation of Faust and Mefistofele. Hear how he delivers the Boito version in what should be an intriguing rarity when Bernard Haitink conducts these Royal Opera concerts at the Barbican.

The Royal Opera's two concert performances of `Mefistofele' are at the Barbican Hall, EC2 (0171-638 8891) tonight & 16 Mar, 7pm