Final answer:
The works The Eve of St. Agnes, La Belle Dame sans Merci, Ode to a Grecian Urn, and Ode to a Nightingale by John Keats were published in different volumes, not as a single collection in 1820.
Step-by-step explanation:
The Eve of St. Agnes, La Belle Dame sans Merci, Ode to a Grecian Urn, and Ode to a Nightingale are all famous works by the English Romantic poet John Keats. These poems were published in 1820, but not all in the same volume. In that year, two of Keats' most acclaimed works, Ode to a Grecian Urn and Ode to a Nightingale, appeared in a volume titled Selected Poems. However, the specific volume that combined the four works mentioned does not align with the 1820 publication date, meaning that they likely appeared in different volumes or subsequent collections that grouped Keats' works together posthumously.
While The Eve of St. Agnes and Ode to a Grecian Urn might have been published in 1820, La Belle Dame sans Merci was first published in 1820 and the version most are familiar with appeared in 1820. Ode to a Nightingale was written in 1819 and first published in 1819 in the volume Annals of the Fine Arts.