One other thing happened during the course of this eventful year: the Carthaginians- destined one day to be our bitterest enemies- crossed for the first time into Sicily to take sides in a local dispute. (IV 30)
It is pretty easy to guess why this isolated sentence comes into Book Four of Livy's history. He wants to indicate what is about to happen- and what several books later will become a theme of his history- the conflict for dominance in the Western Meditereanean between Rome and Carthage- a conflict that we shall obviously consider later. But for now, I think its more interesting to wonder about why Livy writes this- we know why he wrote it, but where did he come across the fact that Carthage was intervening in Sicily (a fact he tells us has nothing to do with Rome at this point) and decide to include it in his history. We know that Livy was interested in Roman historians and in senatorial records- but I would conjecture that what this extract reveals is that Livy was interested in another kind of history, which threw a light on what happened in Rome.
In the south of Italy and in Sicily for years a thriving Greek culture had developed. The earliest Greek colonies were founded at some point in the 8th Century BC. They had become important centres within the Greek world. The playwright Aeschylus spent some of his declining years in Syracuse and may well have died in Sicily and Sappho the poet may well have been exiled there from Mytilene a century before. By the 410s Syracuse was a major Greek power- and amongst the most important actions of the Peloponesian war was the invasion of Sicily by Athens- an invasion successfully resisted. So Sicily was important and was part of the civilised Greek world- which meant it was probably literate and probably had its own- now lost- histories. That would suggest that Sicilians recorded the event described in Livy- there is no reason for a Roman chronicler to have recorded it as according to the historian this event did not effect the Romans. So it would seem a fair assumption- that Livy took it from a Sicilian chronicler- but why was Livy reading things in Sicily?
Here I think we have something more important than Livy's warning to his readers- we have an indication of how he worked at early Roman history and about one of the non-Roman sources that Livy used. This argument is not conclusive- though it is backed by the scholarly introduction of the edition I'm using- but it would seem likely that Livy was reading Sicilian chronicles and probably southern Italian chronicles (where there was also a Greek culture) to learn about events further north in the peninsular. He must have grabbed this particular incident- the first mention of Carthage and decided to put it in his history. That would indicate that behind some of Livy's history lies the sources he mentions- the Roman historians, the records in the temples that we have discussed and of course his own intelligence as a historian- and behind other parts lies a hidden Greek influence from the lands Magna Graeca (southern Italy and Sicily). I say influence because it may have been refracted through other historians- that we do not know about- but somewhere at the source of some of Livy's history of Rome are accounts of the history of Sicily and southern Greece which mention, occasionally, events to the north and allowed Livy to realise the date of the first Carthaginian involvement in Sicily.