This is not to say that Polybius was the first to write a history of Rome’s wars. While narrative history seems to have been a relatively late development in the city, Rome had some form of record keeping that went back to, at least, the early fourth century BC and likely much earlier. By 200 BC, Roman elites had also begun to write narrative accounts of their city’s past, including warfare, initially in Greek and later in Latin. By the time Polybius put stylus to parchment, Roman history was a thriving genre. And yet, what Polybius did, especially with respect to the Roman army, was novel. While Polybius’ explicit focus was on the rise of Rome, he also worked to place events and developments within a Greek historical and historiographical context. He clearly used material from native Roman sources, but he put it into a Hellenistic historical framework, fusing these two great traditions to create a truly innovative masterpiece of historical literature. Within this, Polybius offered the first systematic view of the Roman war machine.
As with any masterpiece, however, Polybius’ work can be difficult to analyze. On the surface, Polybius presents himself as, and has been understood to be, a very sober and reliable witness. In the opening of his work (Polybius 1.4) he criticizes other historians for their uncritical approaches and their use of dubious evidence, promoting his own analytical techniques and use of eyewitness testimony
