It is interesting to me that Livy's preface begins with the first four feet of a dactylic hexameter:
Facturusne operae pretium sim...
In other words, he inaugurates his prose history with the trappings of epic. This is only the first indication in the preface that Livy has poets on his mind.
He refers again to poetry when commenting on his refusal either to attempt to substantiate or refute the accounts of Rome's earliest days:
Quae ante conditam condendamve urbem poeticis magis decora fabulis quam incorruptis rerum gestarum monumentis traduntur, ea nec adfirmare nec refellere in animo est.
And, in a nice bit of ring-composition-cum-variatio, he ends the preface with a reference to 'the poets':
Cum bonis potius omnibus votisque et precationibus deorum dearumque, si, ut poetis, nobis quoque mos esset, libentius inciperemus, ut orsis tantum operis successus prosperos darent.
This is a present contrary-to-fact condition: 'If I were a poet, I would begin...'; in other words, he's not a poet, so he won't begin in such a way.
Or will he? By raising the issue in the first place, in a sort of praeteritio, he's already put such an invocation in the minds of his readers, his denials notwithstanding. And it's not as though he hasn't been thinking about the gods in the course of this preface:
Datur haec venia antiquitati, ut miscendo humana divinis primordia urbium augustiora faciat, et si cui populo licere oportet consecrare origines suas et ad deos referre auctores, ea belli gloria est populo Romano ut, cum suum conditorisque sui parentem Martem potissimum ferat, tam et hoc gentes humanae patiantur aequo animo quam imperium patiuntur.
Some questions to ponder: what, exactly, is the relationship of Livy's history to epic poetry? Was he attempting to write 'epic in prose'? How close are the parallels we can draw between his treatment and use of foundation myths and the treatment and use of them made by Vergil?
I realize that these are questions that have probably been addressed at length in the scholarship. Nevertheless, they're some questions that came up as I was reading the preface, and it's always good to try to take a fresh look. And it's better, perhaps, to try to come up with some ideas and theories before rushing to the answers that have already been given.
As always, any comments or feedback is welcome.