"The Happiest Day" or, "The Happiest Day, the Happiest Hour" is a six quatrain poem . It was first published as part of in Poe's first collection Tamerlane and Other Poems. Poe may have written it while serving in the army. The poem discusses a self-pitying loss of youth, though it was written when Poe was about 19.
A nearly identical poem called "Original" written by Poe's brother William Henry Leonard Poe was first published in the September 15, 1827 issue of the North American. It is believed Poe wrote the poem and sent it to his brother, who then sent it to the magazine. T. O Mabbott felt that the rather tepid value of this slightly edited version of the poem suggests that they were made by William Henry, though perhaps with Edgar's approval.