No Wagner opera divides people more than Parsifal. For some it is Wagner's masterpiece, a work that takes the musical developments already evident in Tristan even further. For others it is a work of moral starvation, of intense spirituality that more than any other Wagner work is explicitly about the redemption of the Aryan German. Its appropriation by the Nazi's in the 1920s and 1930s, and the moral abyss that lead to the Holocaust, make it the most loathed of Wagner's great works. It is, like all Wagner, banned in Israel, yet, ironically, was premiered by the Jewish conductor, Hermann Levi in 1881 (admittedly to Wagner's initial fury).

Left: Detail from "Parsifal Revealing the Holy Grail" by Franz Stassen (1869-1949), from: Parsifal: A Drama by Wagner Retold by Oliver Huckel, 1903.

One of today's greatest interpreters of the opera is Daniel Barenboim, whose recording with the Berlin Philharmonic on Teldec (9031-74448-2) is as devotional a recording you will hear. Parsifal is politically problematical because there remains in the music a distillate of Wagner's personality, not least in the figure of Klingsor, the evil genius of the drama, a character who comes to embody the corruption of Judaised Christianity. Yet the problem goes much deeper because whilst the ideas may be repellent, no opera fuses words, music and drama into such a perfect communion.

For truly great performances of Parsifal on record (and there are very few) you have to look back in time, and invariably to the Bayreuth Festival. Hans Knappertsbusch conducted many performances at Bayreuth after the war and of these his1962 recording is the best, a visionary and cultured reading. Even greater, however, are these recordings on Naxos of Karl Muck conducting Parsifal, excerpts from Acts I and II, with Act III almost complete. Recorded in the studio, with Bayreuth forces, in 1927 and 1928, they are unmatched, particularly the final act which receives the greatest performance yet to appear on disc. No where else is the symphony of this act so compellingly realised.

Karl Muck is the nearest we have to a direct Wagner link, mainly through his relationship with Wagner's widow, Cosima. Born in 1859, he conducted Parsifal regularly at Bayreuth after 1901 and became something of a Wagner specialist. Comparable to Toscanini, Strauss and Weingartner in his advocacy of objective music making, his Wagner is noted for a disciplined clarity, with textures opening up to reveal the pulse of the music. These fine recordings, the outcome of sessions he did with Columbia, are representative of this.

Parsifal opens with a long prelude that sets the tension for the whole opera, a tension that is never released until the heavenly choral conclusion of Parsifal conducting communion with the Knights of the Holy Grail. The music at points reaches stasis, and in no other opera does Wagner rely on pure silence to achieve the effect of etherealism. Muck's conducting of the prelude is very slow (in my experience only Toscanini has been slower on a 1930s BBC recording, although that performance lacks mystery). The breadth of the tempo, from the opening in A flat major, makes the most of blending the themes played out on violins and cellos and combined clarinets and bassoons. The wind chorale that symbolises the guilt of Amfortas is played with pungency and the hushed, tremolando strings are precisely that. Few preludes on record are as clearly shaped and defined as this with the vast diatonic spaces of the music given a supreme nobility.

Similar depth of sound and tension are evident in the playing of the "Transformation Music" to Act I. This extraordinary, angst-ridden music is one of Wagner's great creations, music of extreme dissonance and languorous lamentation. Trombones bray above a great swathe of lush string melody as the music seems to both collapse and rise under the weight of the march that precedes the tolling of the bells. These bells, an ostinato theme in C, G, A and E appear firstly alone, but later play in unison with the bass instruments. Originally, Wagner had suggested that Chinese tamtams might offer the sound he needed, but in the end he had specially constructed metal canisters made to achieve the appropriate pitch. These became known as the Bells of Monslavet, and are heard on this recording (the only recording to exist with the original bell sounds. The bells were melted down by the German's during World War II.). The effect is very different from most performances of this scene you will hear - where the sound is invariably much brighter. Here there is a real hollowness and terror to the sound.

As I have suggested, Act III is the most symphonic of the opera. Here Muck includes all the major orchestral interludes - the prelude, the Act III Transformation Music and the Good Friday Music. The Act III Prelude probably includes the most desolate music Wagner ever wrote and although thematically the music is similar to the Act I Prelude its despondency is less clearly navigated by many conductors. The second act ends in the black key of B minor, and right from the outset of the prelude Muck makes the tension between B major and B flat minor the key to his interpretation. This music is all about anguish, despondency and distress. It fails to elude to the fact that it is now springtime, the music sinking under the weight of its own interminableness. By contrast, his reading of the Good Friday Music is light and lyrical, with an almost vocal strength deriving from his balancing of the textures. In few Wagner records is the tension between gravity and nature as well manipulated as here. Where needed, Muck can compel his musicians to make the right sound: an astringent oboe here, a cavernous brass sound there, strings ladened with depth. The superb playing makes understanding this opera slightly easier: polyphony and dissonance are materially integrated, layers of chords and voices are skillfully overlapped.

And the singers? Both Pistor (as Parsifal), singing in true Heldentenor style, and Hofmann (as Gurnemanz) are natural Wagnerians, two-a-penny in the 1920s but almost extinct today. Moreover, they were both familiar with Bayreuth and Muck's interpretation of Parsifal. Bronsgeest plays an anguished Amfortas. Alexander Kipnis, in a separate reading of the Good Friday Spell under the baton of the composer's son, Siegfried, is superbly dark and broad-toned.

The transfers of these legendary recordings are quite astonishing, and certainly the best to have yet appeared. The recording, although dating from just two years after microphone recording became possible, offer clear acoustics and real bloom. There is a very natural surrounding spaciousness, the strings remastered with their depth intact, the Monslavet Bells clearly unique, and the brass and woodwind capable of the most focused forte. The importance of the recording itself underlines why the 1913 recordings under Alfred Hertz are only of slight interest. Although one of the most ambitious recording projects of the acoustic era it is evident how crowded the sound is, with balances often very wayward indeed. The brass is often very clearly evident, whilst the strings barely register.

"The Attainment of the Holy Grail" (1898-99) by Edward Burne Jones. Stanmore Hall Tapestry

Is an edited version of Parsifal over 70 years old worth investing in? The answer must be an emphatic yes. Apart from the very low cost, these are Wagner recordings of an altogether different era. Karl Muck offers unique insights into this work in recordings that are very serviceable, and require minimal adjustment for the listener. As a supplement to a great single recording they are invaluable.