Ever since Hesiod's famous encounter at the beginning of the Theogony (most famously remembered by Callimachus in fragment 2 of the Aetia), the introduction into any poem of the Heliconian Muses, patron goddesses of literature itself, has always been a moment for the poet to turn in on himself (or rather, perhaps, to stand outside himself) so as to contemplate more obtrusively than elsewhere the nature of his own craft.