Citizenship in a sustainable empire
Life is pretty sweet for Roman citizens who are actual citizens. Polybius describes how seriously men strove to construct a fair, balanced government through the Senate, the enfranchisement of the citizen in court, and the introduction of legal jurisprudence. In other words, Rome is a forerunner to the modern society of the West. The nation celebrates its people, and Polybius sees that there are potential weaknesses in the government, but all in all, the Roman government is sustainable.
The Punic Wars
Punic is an archaic word that refers to the Phoenician origin of the people who lived in Carthage. These wars were considered by Polybius in ways that might remind the reader of the World Wars. The Punic Wars changed the game of empire building. When the Romans were able to completely absorb the Carthage nation, the tone was set: What else could the Romans conquer, potentially? Polybius realizes that the fall of Corinth means something very specific for Europe and the Mediterranean world: It means the Roman Empire is about to come into its full power.
The importance of human events
Polybius clearly demonstrates his belief that great actions belong in the annals of history. A historian is someone who says, "People should be writing this stuff down! I will write it." Polybius is a well-informed person with repute in his community, and he's a citizen, so he is inclined to celebrate Rome. This shows that he views his own life and experience as an important part of the historical process, perhaps because he sees that the new events in recent history are going to shape the future.