For not by art does the poet sing, but by power divine. Had he learned by rules of art, he would have known how to speak not of one theme only, but of all; and therefore God takes away the minds of poets, and uses them as his ministers, as he also uses diviners and holy prophets, in order that we who hear them may know them to be speaking not of themselves who utter these priceless words in a state of unconsciousness, but that God himself is the speaker, and that through them he is conversing with us.
PlatoMany are the noble words in which poets speak concerning the actions of men; but like yourself when speaking about Homer, they do not speak of them by any rules of art: they are simply inspired to utter that to which the Muse impels them, and that only; and when inspired, one of them will make dithyrambs, another hymns of praise, another choral strains, another epic or iambic verses- and he who is good at one is not good any other kind of verse: for not by art does the poet sing, but by power divine.
Plato