Thomas de Hartmann (1885-1956) was one of musical history’s ‘nearly men’. As Elan Sicroff – the pianist in all three Nimbus releases here – noted in his informative April Gramophone blog, ‘Why Thomas de Hartmann?’, the initial acclaim of his youth in tsarist Russia gradually waned in exile in the West to death in obscurity in New York. Yet he was known to a large and celebrated circle of friends and colleagues that included Casals, Kandinsky (three of whose paintings adorn the booklet covers), Koussevitzky, Tortelier and many more. A pupil variously of Arensky (composition), Taneyev (counterpoint), Esipova-Leschetizky (piano) and Mottl (conducting), his ballet La fleurette rouge (1906) was danced by Nijinsky, Karsavina and Fokine. He was, as much as were Stravinsky and Steinberg pre-1914, a Great Hope of Russian music.

For most listeners (if they are aware of him at all), Hartmann’s reputation rests on his collaborative piano pieces with his sometime mentor, George Gurdjieff (Wergo, 1/99). However, Hartmann’s true stature and range as a composer (not to mention his Ukrainian heritage) are apparent from Nimbus’s two discs of piano music, beautifully played by Sicroff, fully in tune with the diverse idioms from all stages of the composer’s career. As with Stravinsky, Hartmann’s style altered over time, becoming more radical as he aged, and both discs chart that progress clearly. The gauche, almost naive writing of the early Trois Morceaux (1899; No 1’s absence is unexplained) or Three Preludes (1904) gradually gave way to more modern influences, such as Stravinsky in the Divertissements from Forces of Love and Sorcery (1915) and Musique pour la fête de la patronne, d’après Degas (1947). The Twelve Russian Fairy Tales (1937) highlight the strengths and limitations of his musicality, charming vignettes of Russian folklore aimed at children (Stokowski orchestrated some), but ‘The Witch’s House on Hen’s Legs’, ‘Baba Yaga’ and ‘Kasstchei the Deathless’ are tame compared with better-known evocations by Mussorgsky, Liadov or Stravinsky. Nonetheless, the more cerebrally expressive world of the two piano sonatas (1942; 1951) and the Two Nocturnes (1953) shows Hartmann on a very high plane of attainment indeed.

Hartmann’s output eventually included operas, symphonies and concertos – recordings of which we will have to wait for – and chamber music, two discs of which Nimbus has also released. As with the piano set, this pair of chamber discs combines smaller, salon-like items – such as the Feuillet d’un vieil album, Hommage à Borodine (both 1929) and La Kobsa (1950, looking back to his Ukrainian roots) – and major works such as the sonatas for violin (1936) and cello (1941), both with piano. Only the second chamber disc, however, follows a chronological format, covering the brief span 1941-46 and concluding with the utterly delightful Trio for flute, violin and piano (1946). Chamber disc 1 opens with the fine, mostly lyrical Violin Sonata, keenly performed by Katharina Naomi Paul, especially in the weighty, somewhat Bartókian finale. (Natalia Gabunia handles that disc’s violin miniatures very neatly.) The composer’s own reduction of his Fantaisie Double Bass Concerto (1942), written with Koussevitzky in mind, is magnificently rendered by Quirijn van Regteren Altena. Its wistful central ‘Romance 1830’ has no connection to the song of the same name of 1936. The disc concludes with the set of Ukrainian Christmas carols, Koladky (1940), for saxophone quartet, one of only two works on any of these five discs where Sicroff’s piano is absent (but also playable by strings or piano).

The performances, recorded in Hilversum between 2011 and 2015, are uniformly of the highest quality. Nimbus’s sound is first-rate and all the musicians consistently sound as though they relished Hartmann’s idiomatically conceived, sometimes sinuous melodies, whether cellist Anneke Janssen in the lovely Chanson sentimentale (1929) and Deux Pleureuses (1942), or sopranos Nina Lejderman and Claron McFadden in the songs, or the Amstel Quartet in Koladky.

As with the second chamber disc, the song album is a joy from start to finish, the pieces presented chronologically, from a clutch of charming romances and melodies sung prettily by Lejderman, to larger cycles (those setting Shelley and Joyce sung marvellously well by McFadden) and the unaccompanied vocal quartet La Tramuntana (1949), dedicated to Casals.

If I had to recommend just one performance, it would be (one or two intonational infelicities aside) Janssen and Sicroff’s of the magnificent Cello Sonata, one of the finest for the instrument penned in the 20th century. Occasionally one encounters an unfamiliar work that compels wonderment from the very first bar. Deborah Pritchard’s Wall of Water was one such (Nimbus, 5/15); Hartmann’s Cello Sonata is another – an unalloyed masterpiece with a wonderful variation set at its centre. A revelation