At the urging of Pericles, Athens entered a war with Sparta in 431 BC. The statesman's strategy required the Athenians to refuse an infantry battle, withdrawing behind the city walls to watch the Spartans ravage their farms. Pericles’ status allowed him to convince the Athenians to accept this plan, and he remained popular enough in the first year of the war to be chosen to deliver the annual funeral oration. In this speech Pericles laid out his vision of the Athenians’ special qualities and their right to rule, as well as the need of individuals to sacrifice themselves in the service of their beloved Athens and of the city-state's current power and future glory.

As the war continued and a plague struck Athens, Pericles’ popularity waned. In his final speech in Thucydides he makes a bald case for the glory and advantages of rule over other Greeks and the dangers of letting that rule slip away. The Athenians took out their frustrations on Pericles even as they continued to fight the war he had promoted. Thucydides’ analysis of Pericles as a leader reflects the statesman's admirable qualities, the deficiencies of the leaders who followed him, and the criticisms of those who believed Pericles had corrupted the political process and led Athens into a disastrous war. Looking back on Pericles as an older man, Thucydides sought to defend the leader his own history had shown to be the principal cause of war in 431.