This is a beautiful set, but a curious one. Its release marks the tercentenary of Gluck's birth, an anniversary that hasn't as yet, in the UK at any rate, received anything like the attention it is due. However, deriving from a German radio production in April last year, this brings another, altogether more prominent anniversary into the frame – what we have here is not Gluck's original Iphigénie en Aulide, first heard in Paris in 1774, but a German-language version prepared by Wagner for performance in Dresden in 1847.

That Wagner should be drawn to Gluck was inevitable. The latter's revolutionary demands for a total work of art comprising drama, song and dance, conveyed in music of absolute directness, pre-empt Wagnerian aesthetics. Of all Gluck's operas, it is Iphigénie en Aulide – with its conflicts between human love and divine proscription, and its redemptive heroine willing to sacrifice herself for the greater good – that fits most closely with Wagner's preoccupations.

But unlike Berlioz, whose edition of Gluck's Orfeo ed Euridice still forms the basis of many modern performing versions, Wagner distorts as much as he adapts, and in streamlining Gluck, narrows his range. Dance is integral to Gluck's synthesis, but Wagner cuts the ballet. Passages are re-written to blur the divisions between recitative and aria way beyond Gluck's original intentions. Wagner, chameleon-like, never strays beyond Gluck's harmonic scheme, though his re-orchestration, beefed up with extra wind and brass, sounds Beethovenian at times.

Handsomely conducted by Christoph Spering, and boasting some terrific choral singing from the Chorus Musical Köln, the recording is very fine. The great performance comes from Oliver Zwarg as Agamemnon, dignified, anguished and trapped, Wotan-like, in a hell of his own making. Christian Elsner's Achilles is nicely pitched between hero and bully-boy. Michelle Breedt's Clytemnestra could do with more elemental rage, but Camilla Nylund makes a fine Iphigenia, radiant and noble rather put-upon and father-fixated. It remains, however, something of a wasted opportunity. Wagner's Iphigenia is just not as good as Gluck's, a new recording of which would have been infinitely preferable.