Arne Garborg’s epic poem-cycle Haugtussa (‘The Maid from under the Mountain’) is a classic of Norwegian literature, its four volumes covering a vast panoply of human and supernatural interaction, concentrated on the heroine Veslemøy synsk (‘far-sighted Veslemøy’ or ‘Veslemøy the seer’). Love, betrayal, self-sacrifice, redemption, lust, creatures from the underworld and ultimate forgiveness rub shoulders vividly through its pages like a fusion of the Eddas, Peer Gynt, the folk-ballad Draumkvaedet and the Divine Comedy. If that sounds unfamiliar from the world of Grieg’s wonderful nine-song cycle, this is because the master of Bergen concentrated on just the strand of Veslemøy’s doomed love for Jon, omitting the wider contexts of Garborg’s extraordinary conception.

As Thommessen writes in the booklet, Grieg ‘had enough material to complete a larger work based on the cycle; I have just taken the liberty of doing the work for him’. The result is four times the size of Grieg’s cycle, a two-hour cycle for mezzo-soprano and piano (not an opera, as frequently listed on online retail sites that should know better) comprising 44 songs and a virtuoso piano cadenza (disc 2 tr 15), though the writing is incredibly demanding for both performers throughout. The musical language is a challenging collage, Thommessen using almost Grieg’s entire oeuvre from Haugtussa to the Opp 13 and 45 sonatas and Piano Concerto for raw material, yet set in a recognisably postmodernist harmonic framework (I won’t spoil your fun spotting the quotes but there is a crib-sheet on page 11).

Marianne Beate Kielland sings, and occasionally speaks and wails, superbly throughout, catching the ardour of Veslemøy’s love for Jon (songs 16‑21) as beautifully as she portrays the heroine’s slow descent towards the Underworld. This is a nightmarish dream-sequence finally entered in song 34, precipitated by her distress at Jon’s wedding to another, two songs before. The radiance of the final pair of songs is entrancing. Mortensen proves a fine partner (and more than a ‘mere’ accompanist), supporting Kielland and exposing Thommessen’s intricate musical web with great clarity. 2L’s sound quality is superb and the set comes with a Blu-ray film of the whole. But this is music to be heard and relished in the imagination. Hugely recommended.