[2] Horenstein is particularly remembered as a champion of modern music and as a Mahler conductor, although his repertory as shown by his discography was quite wide.
[3] Horenstein conducted the works of Bruckner and Mahler throughout his career, and he also displayed ongoing interest in Carl Nielsen, whom he knew personally, at a time when these composers were unfashionable.
A number of radio archives hold broadcast airchecks of many of the other Mahler symphonies, as well as Das Lied von der Erde.
[5] Horenstein also recorded Robert Simpson's Third Symphony and music by Paul Hindemith and Richard Strauss during the last few years of his life.
His final operatic, and British, engagement was his March 1973 performances at the Royal Opera House, Covent Garden of Richard Wagner's Parsifal.
[6][7] It was during a performance of Nielsen's Fifth Symphony in Minneapolis in 1971 that Horenstein suffered a heart attack and was caught in mid-air by the leader of the orchestra.