Shakespeare's poem laments the recent deaths of the Phoenix and a Turtledove.No one knows for sure who or what these allegorical birds represent.For a long time the most popular guess was Elizabeth I and Essex, though they do not really fit.
This is not a work of visual art, however, but a poem, Shakespeare's "The Phoenix and Turtle." Although Shakespeare's enigmatic, allegorical poem has never been seen as a source for Keats's ode, it is its principal source.
Moreover, intertextuality linking the two poems is so extensive that it amounts to allusion and more even than that.
(3) His copy of The Poetical Works of William Shakespeare (1806)--acquired in 1819, the year he wrote "Ode on a Grecian Urn"--contains "Threnos," the last five stanzas of "The Phoenix and Turtle." (4) While it is arguable that he read and refers solely to these stanzas, we shall see that he seems to engage the entire poem.
His reading was not, after all, limited to the books in his library--he and his friends regularly lent one another books, and in November 1917, two years before acquiring The Poetical Works, he was reading "Shakespeare's poems" in an unspecified edition (Gittings 162).
This re-expression is so extensive that, it seems fair to say, Keats is enlisting Shakespeare as co-author. Shakespeare is Keats's "Chief Poet" ("On Sitting Down to Read King Lear Once Again" 7).
We know that Keats read and reread Shakespeare intensively from mid-March 1817, the plays primarily but also the sonnets (Gittings 120).
There is every reason to assume that he read "The Phoenix and Turtle." It would be surprising if he had not, though he makes no mention of it in his letters.
The finale of his ode is the primary indication that he read it, and it is a convincing indication.
The urn is apparently decorated with a picture of a youth playing a flute in a pastoral setting and a young man chasing a young woman around the urn.
It's from a poem, "Ode On A Grecian Urn," written by John Keats in May, 1819, when he was about 24.