Gustav Mahler was considered one of the greatest opera conductors of his time; he could even be called the first intercontinental star conductor. But that was not the case with his music; until the 1960s his compositions were only performed by specialists, the pieces nowhere near belonging to the standard repertoire.

Today, however, performances of Mahler's music rival those of Beethoven's in frequency, thus counting Mahler among the most successful symphonists. What happened to cause that c...