The Sunday morning concert of the two-day Once upon a time in the 20th century... promises some truly special chamber music pieces featuring such outstanding performers as Alina Ibragimova, Mihály Berecz, Csaba Klenyán and Dóra Kokas.

Anton Webern was inspired by feelings of love in 1905 when he wrote Langsamer Satz. Emotional and lyrical, the music radiates both longing and tranquillity, evoking the world of Late Romanticism: the composer, a student of Schönberg’s, had not yet employed the strictly atonal musical language he later employed. The piece, intended as part of a string quartet of which it was the one movement that was completed, before being lost for a good half-century, will be performed by the Keller Quartet.

Alban Berg’s Adagio is the slow movement from the chamber concerto for violin, piano and wind instruments he wrote between 1923 and 1925. The profoundly emotional and romantic piece, which uses the dodecaphony technique while retaining a strongly lyrical tone, was subtitled Love by the composer, and is often performed independently in a trio version comprised of violin, clarinet and piano.

Only one movement survives from Mahler’s romantic, emotional and dark-sounding A minor piano quartet, written around 1878. One of the composer’s earliest chamber music works, it dates from his student years at the Vienna Conservatory. Nevertheless, it already foreshadows his later dramatic style.

The fourth piece of the concert will be the 1899 string sextet Verklärte Nacht (‘Transfigured Night’). One of the young Schönberg’s most important works, it is considered the pinnacle of Late Romantic chamber music. The first programme music ever written for a chamber ensemble, it depicts a couple’s dramatic walk through a forest in the language of music, based on Richard Dehmel’s poem of the same name.