John Keats was born in Moorgate London, England on October 31, 1795. He became fully dedicted to writing poetry in 1817, and wrote When I Have Fears That I May Cease to Be in January of 1818. And on February 23, 1821, John Keats passed away in Rome, Italy.

Sources:

https://www.britannica.com/biography/John-Keats/The-year-1819

https://en.wikipedia.org/wiki/John_Keats

https://erling.yoga/john-keats-isle-of-wight/

https://www.christies.com/features/Joseph-Severn-portrait-of-Keats-11258-1.aspx