P. B. Shelley mourns over the death of John Keats in his famous elegy -

Adonais, pastoral elegy by Percy Bysshe Shelley, written and published in 1821 to commemorate the death of his friend and fellow poet John Keats earlier that year.

Shelly was an English Romantic poet whose passionate search for personal love and social justice was gradually channelled from overt actions into poems that rank with the greatest in the English language.
His other famous literary works are:
- Prometheus Unbound (1820),
- A Defense of Poetry (1820),
- Ode to the West Wind,
- To a skylark,
- The Revolt of Islam,
- Alastor,
- Ozymandias,
- Queen Mab,
- The Cloud.

Source: Britannica.com