He continued his recently acquired habit of devoting his summer vacations, in the Austrian Alps, to composing, and, since, in his case, this involved a ceaseless expenditure of spiritual and nervous energy, he placed an intolerable strain on his frail constitution. Most of the works of this middle period reflect the fierce dynamism of Mahler’s full maturity. An exception is Symphony No. 4 (1900; popularly called Ode to Heavenly Joy), which has a song finale for soprano that evokes a naive peasant conception of the Christian heaven. At the same time, in dispensing with an explicit program and a chorus and coming near to the normal orchestral symphony, it does foreshadow the purely orchestral middle-period trilogy, Nos. 5, 6, and 7. No. 5 (1902; popularly called Giant) and No. 7 (1905; popularly called Song of the Night) move from darkness to light, though the light seems not the illumination of any afterlife but the sheer exhilaration of life on Earth. Between them stands the work Mahler regarded as his Tragic Symphony—the four-movement No. 6 in A Minor (1904), which moves out of darkness only with difficulty, and then back into total night. From these three symphonies onward, he ceased to adapt his songs as whole sections or movements, but in each he introduced subtle allusions, either to his Wunderhorn songs or to his settings of poems by Friedrich Rückert, including the cycle Kindertotenlieder (1901–04; Songs on the Deaths of Children).
At the end of this period he composed his monumental Symphony No. 8 in E-flat Major (1907) for eight soloists, double choir, and orchestra—a work known as the Symphony of a Thousand, owing to the large forces it requires, though Mahler gave it no such title; it constitutes the first continuously choral and orchestral symphony ever composed. The first of its two parts, equivalent to a symphonic first movement, is a setting of the medieval Catholic Pentecost hymn Veni Creator Spiritus; part two, amalgamating the three movement-types of the traditional symphony, has for its text the mystical closing scene of J.W. von Goethe’s Faust drama (the scene of Faust’s redemption). The work marked the climax of Mahler’s confident maturity, since what followed was disaster—of which, he believed, he had had a premonition in composing his Tragic Symphony, No. 6. The finale originally contained three climactic blows with a large hammer, representing “the three blows of fate which fall on a hero, the last one felling him as a tree is felled” (he subsequently removed the final blow from the score). Afterward he identified these as presaging the three blows that fell on himself in 1907, the last of which portended his own death: his resignation was demanded at the Vienna Opera, his threeyear-old daughter, Maria, died, and a doctor diagnosed his fatal heart disease.
Thus began Mahler’s last period, in which, at the age of 47, he became a wanderer again. He was obliged to make a new reputation for himself, as a conductor in the United States, directing performances at the Metropolitan Opera and becoming conductor of the Philharmonic Society of New York; yet he went back each summer to the Austrian countryside to compose his last works. He returned finally to Vienna, to die there, in 1911. The three works constituting his last-period trilogy, none of which he ever heard, are Das Lied von der Erde (1908; The Song of the Earth), Symphony No. 9 (1910), and Symphony No. 10 in F Sharp Major, left unfinished in the form of a comprehensive full-length sketch (though a fulllength performing version has been made posthumously). Beginning as a song cycle, it grew into “A Symphony for Tenor, Baritone (or Contralto) and Orchestra.” Yet, he would not call it “Symphony No. 9,” believing, on the analogy of Beethoven and Bruckner, that a ninth symphony must be its composer’s last. When he afterward began the actual No. 9, he said, half jokingly, that the danger was over, since it was “really the tenth”; but in fact, that symphony became his last, and No. 10 remained in sketch form when he died.