But the return to free accentual verse in the "Christabel" was an innovation at the beginning of the nineteenth century.

It is to be noted, too, that there are lines of three and even of two accents in Part I.
In chap.XV.of the _Biographia Literaria_, in a list of the "specific symptoms of poetic power" in Shakespeare's early work, Coleridge places first "the perfect sweetness of the versification; its adaptation to the subject; and the power displayed in varying the march of the words....
The sense of musical delight, with the power of producing it, is a gift of imagination; and this, together with the power of reducing multitude into unity of effect, and modifying a series of thoughts by some one predominant thought or feeling, may be cultivated and improved, but can never be learnt.

It is in these that _Poeta nascitur non fit_." "Kubla Khan" is the remembered fragment of a dream.

All that we know about it is contained in the note Coleridge prefixed to it in the pamphlet of 1816.

In the summer of 1798 (Coleridge says 1797, but this seems to have been a slip of his memory[1]) "the author, then in ill health, had retired to a lonely farm-house between Porlock and Linton, on the Exmoor confines of Somerset and Devonshire.