Carl Nielsen 
I always feel a little suspicious when the works of a particular composer need “promotion,” don’t you?
The first such composer who comes to mind is Paul Hindemith. Back in the 1940s, my parents attended some meetings of a Hindemith Society in New York, an organization that endeavored to teach music-lovers about the system that Hindemith (1895-1963) used to compose music. The society also aimed to encourage listeners to appreciate his works. Today, several Hindemith societies still exist, including the Hindemith Institute in Frankfurt, Germany. And then there are the efforts of my alma mater, The Yale School of Music, which mounts occasional attempts to encourage people to contribute money to the School in the memory of Hindemith, who taught composition there after he came to America. I have no idea how well the school’s Hindemith-based fundraising works. (I took a semester-long graduate seminar on the music of Hindemith at the Yale School when I was a student there; it wasn’t very interesting.)
Let’s face it. Despite promotional efforts, the music of Hindemith remains essentially dull.
Yes, there were some early works that tilted toward being avant-garde, like his early Kammermusikcompositions. Later, as Hindemith began to formulate a system of composition, things got more boring, and pretty much stayed that way. His sonatas and other works for stringed instruments are beloved by string players – Hindemith was a viola-player and wrote well for stringed instruments.  His operas Mathis der Maler and Harmonie der Welt gained some traction for a time, but failed to sustain interest or gain a place in the standard repertory.

The Case of Carl Nielsen (1865-1931)

I have to observe that it is difficult to distinguish between the “discovery” and the “promotion” of a composer and his or her works. But it nonetheless seems to me that the works of Carl Nielsen fall into the latter category. Here in the U.S., it was Leonard Bernstein who, during his years at the New York Philharmonic, began to program Nielsen’s works more extensively. More recently the Philharmonic’s current music director, Alan Gilbert, has been programming more Nielsen for his New York audiences. He and the Philharmonic are also engaged in an extensive effort to record all of the composer’s orchestral works.

Nielsen vs. Mahler (1860-1911)

It could be argued that Bernstein also promoted the works of Gustav Mahler. If that was the case, his promotion of the music of Mahler succeeded a lot better, as orchestras now perform Mahler symphonies and his other works all the time.

There are, however, significant differences between the histories of Nielsen and Mahler, not to mention their music. In the years before Bernstein began to program a lot of Mahler, Mahler’s works had not fallen out of the international orchestral repertoire. In fact, they were played a lot, and very well. I am thinking especially of the luminous recordings that Otto Klemperer and Bruno Walter made of Mahler’s Symphony No. 4.During those same years, the works of Nielsen were played most often in his native Denmark.

As all music-lovers know, Mahler’s works became wildly popular with New York audiences, and Bernstein went on to program them more extensively in his concerts in other cities and countries. That success is due to many factors. The music of Mahler synched quite well with Bernstein’s highly demonstrative conducting style. It is a controversial thing to say, but I also suspect that New York audiences loved Mahler’s music because it is so neurotic, and New Yorkers are the most neurotic people in the world.

The music of Nielsen remains a harder sell. It is beautifully conceived and orchestrated. It takes a great orchestra to play Nielsen capably.

Yet to me – and feel free to challenge me on this view – the works of Nielsen are a sidebar to the history of 20th Century classical music, not a central issue, and not really great music. I admire the efforts of Maestro Gilbert and his great orchestra to present worthy orchestral works and to broaden programming. Yet despite all the efforts of both Bernstein and now Gilbert, getting people to adore Nielsen is going to be a tough sell.