In the fall of 1901 Gustav Mahler met Alma Schindler, the beautiful daughter of Emil Schindler, a highly respected Viennese landscape painter and perhaps the most important Austrian visual artist of the nineteenth century. As the story goes, Mahler immediately sat down and composed this Adagietto as a declaration of his love (having written the first two movements of his Symphony No. 5 earlier that summer).
 Alma Schindler
The Dutch conductor Willem Mengelberg, in his personal copy of the Fifth Symphony, wrote: “This Adagietto was Gustav Mahler’s declaration of love for Alma! Instead of a letter, he sent her this in manuscript form; no other words accompanied it. She understood and wrote to him: He should come!!! (both of them told me this!).” Mengelberg’s own description of the Adagietto was “love, a love comes into his life.”

The fact that the music included a reference to Wagner’s Tristan und Isolde may have been an acknowledgment that Alma was herself an accomplished musician and composer and would immediately understand the reference.

Mengelberg also wrote a short poem into his conducting score, words to go with the melody in the first violins.

“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.”

(How much I love you, you my sun,
I cannot tell you that with words.
I can only lament to you my longing and love.)

The music is written for only strings and harp. Mahler’s markings in the score clarify exactly what he wanted from a performance: espressivo, seelenvoll (“soulful”), and mit innigster Empfindung (“with the most heartfelt sentiment”). Beginning very quietly, this music is soon full of longing: its arcing, graceful melodies unfold with a bittersweet intensity, rise gradually to a soaring climax, and finally fall back to the peaceful close.