Gustav Mahler composed his Symphony no. 1 in D major between 1887 and 1888, while serving as second conductor at the Leipzig Opera. First described as a Tone Poem, it was premiered at the Vigadó Concert Hall, Budapest in 1889. The work calls for a large orchestra consisting of approximately 100 musicians, and , and the performance time is between 80 and 90 minutes.

Reference : https://musopen.org/music/2993/gustav-mahler/symphony-no-1-in-d-major/