[Composed at Bishopsgate Heath, near Windsor Park, 1815 (autumn);
published, as the title-piece of a slender volume containing other
poems (see "Biographical List", by Baldwin, Cradock and Joy, London,
1816 (March). Reprinted—the first edition being sold out—amongst the
"Posthumous Poems", 1824. Sources of the text are (1) the editio
princeps, 1816; (2) "Posthumous Poems", 1824; (3) "Poetical Works",
1839, editions 1st and 2nd. For (2) and (3) Mrs. Shelley is
responsible.]