The founding members, namely Gervase de Peyer (clarinet), Cecil Aronowitz (viola), Richard Adeney (flute), and Terence Weil (cello) planned a group of twelve players, a string quintet and a wind quintet with harp and piano, that might be expanded by other players, to perform the great octets by Schubert and Mendelssohn, the septet by Beethoven, Ravel's Introduction and Allegro and the Serenade by Arnold Schoenberg.
Other early members included Gervase de Peyer (first clarinet) Emanuel Hurwitz (leader 1956–1972), Ivor McMahon (second violin), William Waterhouse (bassoon), Osian Ellis (harp), James Blades (percussion), Lamar Crowson and Ernst Ueckermann (piano), Peter Graeme and Sarah Barrington (oboe), James Buck (horn), Edgar Williams (bassoon) and Keith Puddy (clarinet), expanded by Colin Chambers (flute and piccolo), Alan Hacker (bass clarinet), Eric Roseberry (piano), Leonard Friedman (violin), Kay Hurwitz (viola), William Bennett (flute), Stephen Pruslin (piano), Leonard Friedman (violin), Hilary Wilson (harp)[2] and Timothy Brown (horn).
In the opinion of William Waterhouse (writing in 1995), "it was the remarkable rapport between this pair of lower strings" (i.e. Terence Weil and Cecil Aronowitz) "which remained constant throughout a succession of distinguished leaders, that gave a special distinction to this outstanding ensemble.
This was followed by the 1962 premiere, and subsequent 1963 recording, of Benjamin Britten's War Requiem, for which the instrumental sections accompanying the English texts had been written specifically for the Melos, and were directed by the composer in the performance.
In 1964 and 1965 the Melos Ensemble played several concerts at the new Wardour Castle Summer School, founded by Harrison Birtwistle, Peter Maxwell Davies and Alexander Goehr.
[10] The ensemble was expanded for single works by Christopher Hyde-Smith (flute), Anthony Jennings and Stephen Trier (bass clarinet), Barry Tuckwell (horn), David Mason and Philip Jones (trumpet), Arthur Wilson and Alfred Flaszinski (trombone), Robert Masters (violin), Manoug Parikian and Eli Goren (violin), Patrick Ireland (viola), Derek Simpson (cello), Hilary Wilson (harp), Marcal Gazelle (piano), James Blades, Tristan Fry, Jack Lees and Stephen Whittaker (percussion), and singers Mary Thomas (soprano) and Rosemary Phillips (contralto).