But the development of human society does not go straight forward; and the epic process will therefore be a recurring process, the series a recurring series - though not in exact repetition.
No poet will ever take the written word as a substitute for the spoken word; he knows that it is on the spoken word, and the spoken word only, that his art is founded.
It seems difficult, sometimes, to believe that there was a time when sentiments now become habitual, sentiments that imply not only the original imperative of conduct, but the original metaphysic of living, were by no means altogether habitual.
That is to say, epic poetry has been invented many times and independently; but, as the needs which prompted the invention have been broadly similar, so the invention itself has been.
But the gravest difficulty, and perhaps the most important, in poetry meant solely for recitation, is the difficulty of achieving verbal beauty, or rather of making verbal beauty tell.
By the general process of epic poetry, I mean the way this form of art has constantly responded to the profound needs of the society in which it was made.
The Border Ballads, for instance, and the Robin Hood Ballads, clearly suppose a state of society which is nothing but a very circumscribed and not very important heroic age.
The epic poet collaborates with the spirit of his time in the composition of his work. That is, if he is successful; the time may refuse to work with him, but he may not refuse to work with his time.
The epic poet has behind him a tradition of matter and a tradition of style; and that is what every other poet has behind him too; only, for the epic poet, tradition is rather narrower, rather more strictly compelling.
