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.
Society is like a stew. If you don't stir it up every once in a while then a layer of scum floats to the top.