This sonnet represents an interesting example of how the date of publication may not be fully indicative of the date of composition or revision. We have three publications of this little poem, only one of which actually occurred in Poe's lifetime, but all with revisions that are almost certainly authorized by Poe: Flag of Our Union (July 7, 1849), Leaflets of Memory for 1850 (issued about October 1849), and The Works of the Late Edgar Allan Poe (1850).
Mabbott says little about the date of composition for the poem other than to mention Poe's February 8, 1849, letter to Annie Richmond, in which Poe notes that the Flag of Our Union has offered to pay $5 for a sonnet (M 1:466). This letter may well pinpoint the origination of the idea for Poe to write a sonnet, but the subject of the sonnet was presumably influenced by the fact that...