John Keats wrote "Ode to a Nightingale" in 1819 after the death of his brother from tuberculosis. The poem explores the speaker's desire to escape from the pains and sorrows of mortal life by following a nightingale into the forest and partaking in its immortal song. Through vivid imagery and symbolic language, Keats depicts the natural world as both a place of refuge and source of melancholy as the speaker wrestles with his own mortality in the face of his brother's death. The shifting tones reflect the emotional turmoil of wishing to find solace in the nightingale's song while still being tethered to reality.