An international political order was offered, ready-made, to the Greek city-states of the sixth and fifth centuries B.C. by the Lydian and Persian and Carthaginian Empires. The Persian Empire systematically imposed orderly political relations upon the Greek city-states which it subjugated; and Xerxes attempted to complete this work by proceeding to subjugate the still independent remnant of the Greek world. These still unconquered Greek city-states resisted Xerxes desperately – and successfully – because they rightly believed that a Persian conquest would take the life out of their civilization. They not only saved their own independence but they also liberated the previously subjugated city-states of the Archipelago and the Asiatic mainland. But, having rejected the Persian solution to a Greek political problem, the Greek victors were confronted with the task of finding some other solution. And it was here that they failed. Having defeated Xerxes in the years 480 and 479 B.C, they were defeated between 478 and 431 B.C. by themselves.
The Greeks’ attempt at an international political order was the so-called Delian League founded in 478 B.C. by Athens and her allies under Athenian leadership. And it is worth noticing, in passing, that the Delian League was modelled on a Persian pattern. One sees this if one compares the accounts of the system which the Athenian statesman Aristeides induced the liberated cities to accept in 478 B.C. with the account – in Herodotus Book vi, chapter 42 – of the system which had been imposed upon these self-same cities by the Persian authorities after the suppression of the so-called “Ionian Revolt” some fifteen years before. But the Delian League failed to achieve its purpose. And the old political anarchy in the relations between the sovereign independent Greek city-states broke out again under new economic conditions which made this anarchy not merely harmful but deadly.
The destruction of the Graeco-Roman civilization through the failure to replace an international anarchy by some kind of international law and order occupies the history of the four hundred years from 431 to 31 B.C. [outbreak of Peloponnesian War to Battle of Actium]. After these four centuries of failure and misery there came, in the generation of Augustus, a partial and temporary rally. The Roman Empire – which was really an international league of Greek and other, culturally related, city-states – may be regarded as a tardy solution of the problem which the Delian League had failed to solve. But the epitaph of the Roman Empire is “too late.” The Graeco-Roman society did not repent until it had inflicted mortal wounds on itself with its own hands. The Pax Romana was a peace of exhaustion, a peace which was not creative and therefore not permanent. It was a peace and an order that came four centuries after its due time. One has to study the history of those four melancholy intervening centuries in order to understand what the Roman Empire was and why it failed.
Toynbee could not help seeing Rome in this way. Did the Pax Romana not last longer than most?
The League had its headquarters on the island of Delos until 454 BC, when Pericles moved it to Athens. It was dissolved on the conclusion of the Peloponnesian War in 404.
Civilization on Trial, OUP, 1948