Lucerne Festival, Switzerland. Mezzo soprano Magdalena Kozená does not only make the heavenly joys resound in the final movement of Gustav Mahler's Symphony No. 4, earlier in the concert, she devotes herself to the seraphic beauty and intimate simplicity of Mahler's Rückert Lieder. Practically all songs that Mahler composed prior to 1900 were based on texts from Des Knaben Wunderhorn, a collection of folk poems published by Clemens Brentano and Achim von Arnim. Since then, Mahler turned exclusively towards one single poet, the Franconian orientalist and translator Friedrich Rückert. Mahler acknowledged that the poems moved him so deeply that he sometimes felt he had written them himself. In the transcendent final Lied, Ich bin der Welt abhanden gekommen, he also quoted a phrase from the Adagio of his fourth symphony. Asked what it meant, he replied that it personifies himself.