Nobody understood it. I wish I could conduct the first performance fifty years after my death. Mahler’s words after the premiere of his fifth symphony in Cologne, 1904. Mahler didn’t want his work to have a key, since one key would not be enough for a whole symphony. This one is around 70 minutes long.
The most famous part, and maybe the most famous Mahler piece, is the fourth, the Adagietto. By it’s very nature it lends itself well for memorials, like those for the 11 September attacks on the US. Conductors cannot really find a common ground about the length though. Willem Mengelberg used around seven minutes, and he was in contact with Mahler. Haitink did the longest, with the Berliner Philharmoniker: almost double. This one is somewhere in the middle.
Nowadays we tend to think of this movement as elegiac, but Mahler meant it as a love song to his wife Alma. He told this to Mengelberg in a letter:
Wie ich Dich liebe, Du meine Sonne,
ich kann mit Worten Dir’s nicht sagen.
Nur meine Sehnsucht kann ich Dir klagen
und meine Liebe, meine Wonne!