This is Keats's last sonnet, written around 1819. The poet envies the star's constancy — fixed, sleepless, hung aloft the night — but at once rejects its icy solitude: he does not wish to shine «in lone splendour», but to have that same permanence upon his beloved's breast.
The poem lives on this tension between the eternal and the mortal. Keats would be unchanging like the star and yet still feel the rise and fall of a breath; and the closing line resolves it without resolving it: «And so live ever — or else swoon to death». Strofia also holds a letter from Keats to Fanny Brawne, the woman often read behind this «bright star».