The history of the Romans from the foundation of the city to its capture, first under the Kings, then under consuls and dictators, decemviri and consular tribunes, wars abroad and dissensions at home, I have set out in five books, covering matters which were obscure both through their great antiquity, like objects dimly perceived in the distance and because in those days there were few written records, the only reliable means for preserving a memory of past events. A further reason was the loss of most of such accounts as were preserved in the commentaries of the pontiffs and other public and private records when the City was destroyed by fire. From now on a clearer and more reliable account can be given of the City's civil and military history, after it made a second start, reborn as it were from its old roots with increased vigour and productivity. (VI 1)
The first paragraph of Livy's sixth book introduces two important themes we need to consider before moving on to the meat of the book. Livy was a textual historian- his understanding was based on written materials because, as he says here, they were 'the only reliable' means for preserving the past. Therefore Livy's historical abilities were limited- by the fact that his hindsight went back as far as the history of literacy and the extant record. That is true of historians today: history is tied to writing. What Livy faced therefore was a project in the early sections of his book of reconstruction: we are looking at an assembly of fragments into a coherent whole rather than a construction of a whole out of the material of evidence. All historians do something of the first- I have heard historians of the modern world claim that ancient history is more difficult precisely because it involves more of the first type of inquiry. We live with limited means and like Livy any inquiry into that distant a past, where records are scant (today we are worse off than Livy was in terms of the written records for the period). Part of Livy's frustration is that he is forced to rely upon an oral tradition that he considers intrinsically unreliable- he is forced to tales of family history and to fables about the Roman past- and we should not see that tendency stopping with the Gallic conquest and retreat- but rather stopping much later, when Rome's history starts being written.
If that process of a change between reliable written and unreliable oral history- in Livy's view- took place later than this passage implies, then why does Livy suggest it took place earlier. What I think is going on here is that Livy wants to set a second beggining to his history- this paragraph functions as an announcement to the reader. Here, Livy is saying, begins the history of Rome as it can be written. Before this, there was obscurity- but here we have the state that will turn into an empire and into the empire that you and I know. That marriage- expressed fundementally through the character of Camillus, Rome's second founder for Livy, is something that is central to the ideology of Livy's text. Its centrality informs this discussion of the historical record- before this we had a fire and have no records, after this we have records. Livy's point may be based on historical occurence- however no archaeological suggests there was such a fire and we know other Roman historians found documents running back into the fifth century. The key fact here though is less about whether Livy was right about the fire- uncertainty in his history continues after this for a long time- but about the point he wanted to make. Here on in, the story of Livy's history is about Rome's advance- through the conquest of the Samnites, the wars with the Etruscans, the Greeks in the south of Italy and eventually the Carthaginians and the conquest of the world. We have a bracket- on the other side of it is the primitive and distant past about which nothing can be said- on this side is empire, the rise of Rome, the rise of civilisation and the written record.
Livy's ideological purpose therefore gives colour to his discussions of the limitations on his historical enquiry. This third foundation of Rome is a moment at which Livy beleives that the continuous history of Rome down to his day begins.