(Letter from Florence, November 1819.) The following version of a Greek epigram on Plato's spirit will illustrate his own method of translation:-- Eagle! why soarest thou above that tomb?
To what sublime and star-y-paven home Floatest thou?
I am the image of swift Plato's spirit, Ascending heaven:--Athens does inherit His corpse below.
Some time in the year 1820-21, he composed the "Defence of Poetry", stimulated to this undertaking by his friend Peacock's article on poetry, published in the Literary Miscellany.

(See Letter to Ollier, January 20, 1820, Shelley Memorials, page 135.) This essay not only sets forth his theory of his own art, but it also contains some of his finest prose writing, of which the following passage, valuable alike for matter and style, may be cited as a specimen:-- "The functions of the poetical faculty are two-fold; by one it creates new materials of knowledge, and power, and pleasure; by the other it engenders in the mind a desire to reproduce and arrange them according to a certain rhythm and order which may be called the beautiful and the good.

The cultivation of poetry is never more to be desired than at periods when, from an excess of the selfish and calculating principle, the accumulation of the materials of external life exceed the quantity of the power of assimilating them to the internal laws of human nature.
The body has then become too unwieldy for that which animates it.
"Poetry is indeed something divine.

It is at once the centre and circumference of knowledge; it is that which comprehends all science, and that to which all science must be referred.

It is at the same time the root and blossom of all other systems of thought; it is that from which all spring, and that which adorns all; and that which, if blighted, denies the fruit and the seed, and withholds from the barren world the nourishment and the succession of the scions of the tree of life.