Helen in the Iliad and Alcinous in the Odyssey both say the same thing: it was the desire of the gods to grant material for a song that led to the terror of the Trojan wars. Helen first of all (she is speaking of Paris, also, knowing that they were the cause of the war to come): 'On us two Zeus has set a doom of misery, so that in time to come we can be themes of song for men of future generations.' Alcinous claims the gods destroyed Troy and the Acheans 'that there might be a song in the ears of men yet unborn'.
The singer, of course, was Homer. But did he compose it? Poets, then, were singers; nothing was written; each performance of epic verse was unique. Accompanied by a lyre, the poet, the singer, would be permitted to improvise, to recast events. But at the outset of the performance, it was necessary to call upon divine assistance: the Muses were invoked.
What did Homer suppose himself to be doing when he sang? According to an interesting book by Finkelkraut, which I paraphrase here, he takes himself to be reporting the truth. No, Homer did not see what happened - he was not present at Troy, and many even say he was blind, but the Muses saw everything; they were eyewitnesses to the events. Even though Homer knows what occurred in broad outline, he calls upon the Muses to help him when his expertise fails. There is a point when he sings:
Tell me now, you Muses who have your homes on Olympus--you are gods, and attend all things and know all things, but we hear only the report and have no knowledge--tell me who were the leaders of the Danaans and their rulers.
True enough, the Muses supply him with details he had no means of knowing.
The Muses were said to be daughters of Zeus and Mnemosyne. Some asked how, if this were the case, the poet could call upon the Muses as eyewitnesses of what happened before the birth of Zeus. Inventive poets gave another genealogy for the Muses, claiming they were born from Uranos and Gaia, gods from an earlier stage in the theogony. The Muses would have to come first of all, else how could a singer like Hesiod compose his epic? But then the theogony can only reach back to the Muses, recounting their birth and their progeny. Before them, darkness, the forgotten.
The gods set the Trojan wars in motion to await the poet who would call upon the Muses to retell the events. But why did the gods, who saw everything, want to hear them told again? And what of the Muses, gods among the gods - why, if they were the ones who would give the poet the gift of song would they want to bring about the wars? Divine caprice? Or was it to hear the changes wrought by the poet, to experience the surprise of the events happening anew in the song?
I think it was this: the gods, all-powerful, receive something over which they can exert no power. They learn once again of the wars of Troy and, with Hesiod's Theogony, of their own birth. What else do they learn? That there is something in the song which escapes and threatens to destroy the gods themselves. Homer and Hesiod give way to a generation of philosophers who agree that the epic poets have already made the gods all too human. In place of the manifold gods of Hesiod and the Olympus of Homer, there is the burning logos of Heraclitus, the divine law, which he refuses to call Zeus.