Dream" sonnet he wrote in April 1819:--

"The 5th canto of Dante pleases me more, and more; it is that one
in which he meets with Paulo and Francesca. I had passed many
days in rather a low state of mind, and in the midst of them I
dreamt of being in that region of Hell. The dream was one of the
most delightful enjoyments I ever had in my life. I floated about
the wheeling atmosphere, as it is described, with a beautiful
figure, to whose lips mine were joined, it seemed for an age; and
in the midst of all this cold and darkness I was warm.
Ever-flowery tree-tops sprang up, and we rested on them,
sometimes with the lightness of a cloud, till the wind blew us
away again. I tried a sonnet on it; there are fourteen lines in
it, but nothing of what I felt. Oh that I could dream it every
night!"

The last long work which Keats undertook, and he wrote it with extreme
facility, was "The Cap and Bells; or The Jealousies, a Fairy Tale," in
the Spenserian stanza. What remains is probably far less than Keats
intended the tale to amount to, but it is enough to enable us to
pronounce upon its merits. The poem was begun soon after Keats's first
attack of blood-spitting in February 1820. It seems singular that under
such depressing conditions he should have written in so frivolous and
jaunty a spirit, and provoking that his last long work (the last, that
is, if we except the recast of "Hyperion") should be about the most
valueless which he produced, at any date after commencing upon
"Endymion." This poem has been said to be written in the spirit of
Ariosto; a statement which, in justice to the brilliant Italian, cannot
be admitted. It may well be, however, as Lord Houghton suggests, that
the general notion was suggested by Brown, who had translated the first
five cantos (not indeed of Ariosto, but) of the "Orlando Innamorato" of
Bojardo. "The Cap and Bells" appears to be destitute of distinct plan,
though some sort of satirical allusion to the marital and extra-marital
exploits of George IV. is traceable in it; meagre and purposeless in
invention; a poor farrago of pumped-up and straggling jocosity. Perhaps
a hearty laugh has never been got out of it; although there are points
here and there at which a faint snigger may be permissible, and the
concluding portion improves somewhat. Keats seems to have intended to
publish it under a pseudonym, Lucy Vaughan Lloyd; and Hunt gave, in _The
Indicator_