The last of the great romantics

"As a composer, conductor, piano virtuoso, chamber-musical pianist and string-quartet cellist, Franz Schmidt was the most complete musician I have come across in my life." Thus wrote Hans Keller on the Austrian composer who was one of the musical giants of the 20th century, and one of the most thoroughly ignored.

"As a composer, conductor, piano virtuoso, chamber-musical pianist and string-quartet cellist, Franz Schmidt was the most complete musician I have come across in my life." Thus wrote Hans Keller on the Austrian composer who was one of the musical giants of the 20th century, and one of the most thoroughly ignored.

That neglect is bizarre when you consider the sheer attractiveness of Schmidt's musical language: it blends a spontaneous lyricism with a natural contrapuntal technique, inhabiting a harmonic world that is richly, unashamedly tonal but often highly chromatic and spiced with juicy dissonance. His music, moreover, uses the standard forms of Western tradition: there are four symphonies, two string quartets, three quintets, two works for piano and orchestra, a substantial corpus of organ music and two operas. His first opera, Notre Dame, has furnished the only piece of Schmidt to achieve any currency, a spine-tinglingly gorgeous Intermezzo that Karajan took into his repertoire and which still pops up every now and then.

The externals of Schmidt's life are pretty ordinary. He was born in 1874 in what was then the Hungarian town of Pozsony and is now Bratislava, capital of Slovakia (though betweentimes, to confuse matters, it was also called Pressburg). His parents were both musical; indeed, his mother, his first teacher, had been a student of Liszt.

Schmidt's childhood training was at the keyboard: he was a gifted pianist and a passionate organist. But it was as a cellist in the Vienna Philharmonic - which even now doubles as the Opera orchestra - that he made his living. His opera-house "galley years", as he called them, lasted from 1896 until 1913, when finally he was able to turn his back on playing to concentrate on composition and teaching. At his death in February 1939, he was one of the most highly respected figures in Austrian music.

Yet though Schmidt had been acknowledged as a master at home, the post-war stranglehold of modernism on the world's musical establishment brought a rejection of his heady late-Romantic style - old hat, they said. Not a note of Schmidt's was heard at the Proms until two years back, when the current Proms planner, Nicholas Kenyon, a man with more catholic tastes than his predecessors, pulled back the curtains on Schmidt's powerfully moving Fourth Symphony, written in 1933 in memory of his only daughter, who had died in childbirth. Schmidt poured all his grief into the music, all the more intense for its complete lack of self-pity.

This Sunday evening Kenyon takes a much bolder step, when the Proms presents Schmidt's most colossal work, the oratorio The Book With Seven Seals, composed between 1935 and 1937. It's a bold piece of planning which deserves to be rewarded with a large audience for, like the Berlioz Requiem performed earlier this season, this is music of such scale that it demands to be heard in the flesh - and this is most probably only its second performance ever in Britain.

As the title suggests, the text Schmidt sets in The Book With Seven Seals is nothing less than the Book of Revelations - an ideal choice for a millennial Proms season. Its cataclysmic vision of the Apocalypse allowed Schmidt to deploy the full panoply of his profound craftsmanship. In Wilhelm Sinkovitz's neat formulation: "He makes use of the expressive techniques of the post-Wagner generation, but he offsets them with a stupendous mastery of classical form." The work is a vast compendium of Schmidt's stylistic hallmarks: majestic fugal textures and innocent pastoral melodies; imperious fanfares and dignified chorales; pungent chromaticism and diatonic directness; driving dissonance and a dancing, flirtatious gypsy idiom - all welded into an overwhelmingly powerful fusion.

The structure, anchored on a series of thrilling choral fugues, echoes that of the Bach Passions, with St John the Divine fulfilling the role of the Evangelist; Schmidt also finds room for several extended organ solos. It's a work with everything.

Part of the reason for Schmidt's neglect may be a suspicion that he had Nazi sympathies. The conductor Georg Tintner, for example, recorded his profound disappointment at seeing Schmidt give the Hitler salute at the premiere of The Book With Seven Seals only two months after the Anschluss in 1938. But I heard Hans Keller and the organist Susi Jeans, both of whom knew Schmidt well, state emphatically, in public and private, that he was never a Nazi - and the Jewish Keller, who was badly beaten by the SS before escaping to Britain, had no reason to go easy on anyone suspected of fascist allegiances. Instead, Keller and his friend Oskar Adler, both quartet partners of Schmidt's, testified to his political naivety.

Yet Schmidt seems to have a sharper sense of his times than the image he presented. When he was asked by some German-nationalist students to suggest a work for them to perform, he recommended Israel Brandmann's Variations on a Hebrew Theme.

And aren't there some double standards in how we think of musicians working under the Nazis? We don't find it strange that, say, Shostakovich or Prokofiev should disguise their own opinions with a public show of conformity as they struggled to survive under Stalin's tyranny. Shostakovich, indeed, seems to have carefully chosen his battles. So why shouldn't Schmidt, like Shostakovich, have opted for a few well-chosen compromises that would allow his music to be heard?

And, as with Shostakovich, there may be a subtext. Stephen Johnson, writer of the programme notes for Sunday's performance, was alerted by an aside in Schmidt's own notes for the 1938 premiere, in which he confessed that he had made a few judicious cuts in the text. So Johnson went back to the Book of Revelations to see what Schmidt had avoided - and he found two very telling omissions. In Chapter 3, verse 9, Christ condemns the Jews as "the synagogue of Satan"; and Chapter 20, verse 6, refers to Christ establishing his kingdom ("Reich") on earth for a thousand years - a phrase Hitler had adapted in 1933 when beginning his own Reich.

In the pro-Nazi fervour of pre-war Vienna, little would have been easier for a composer wanting to curry favour than to retain those passages for some public thumping of the tub.

Instead, Schmidt made sure that his music gave no hostages to fortune; indeed, it is equally possible to read the work, with its message of the death and destruction of the unrighteous, as a commentary on the Nazi era itself. Whatever the truth of the matter, The Book with Seven Seals is a towering masterpiece, and you probably won't hear it again for years. Cancel all outstanding engagements to get to the Albert Hall on Sunday evening.

Royal Albert Hall, London SW7 (020- 7589 8212, www.bbc.co.uk/radio3/proms) Sunday 7.30pm