The conflict was inevitable, though both sides were reluctant to enter upon it; twenty years after the battle of Salamis it broke out. The fact that Athens was trying at the same time to continue the war against Persia and wrest Cyprus and Egypt from it gave her opponents the advantage; she had far overestimated her strength. After a struggle of eleven years (460-449 B.C.) Athens found herself compelled to make peace with Persia and free the Greek mainland, only retaining absolute control over the sea.

Under the rule of Pericles she consolidated her power, and the ideals that lived in her were embodied in splendid creations. She proved herself equal, in spite of all internal instability and crises, to a second attack of her Greek opponents (431-421 B.C.). But it again became evident that the radical democracy, which was now at the helm, had no grasp of the realities of the political situation; for the second time it stretched out its hand for the hegemony over all Hellas, in unnatural alliance with Alcibiades, the conscienceless, ambitious man who was aiming at the crown of Athens and Hellas.

Mighty indeed was the plan to subdue the Western world, Sicily first of all; then with doubled power first to crush the opponents at home and then gain the supremacy over the whole Mediterranean world. But what a united Hellas might have accomplished was far beyond the resources of Athens, even if the democrats had not overthrown their dangerous ally at the first opportunity, and thus lamed the undertaking at the outset.

The catastrophe of the Athenians before Syracuse (413 B.C.) is the turning-point of Greek history. All the opponents of Athens united, and the Persian king, who saw that the hour had come to regain his former power without a struggle, made an alliance with them. Only through his subsidies was it possible for Sparta and her allies to reduce Athens—until she lay prostrate. And the gain fell to Persia alone, however feeble the kingdom had meanwhile become internally. Sparta, after overthrowing the despotism of Lysander, made an honest attempt to reorganise the Greek world after the conservative programme, and to fulfil the task laid upon the nation in the contest with Persia. But she only furnished her opponents at home, and particularism, which now immediately turned against its former ally, an occasion for a fresh uprising, which Sparta could master only by forming a new alliance with Persia. After the peace of 386 the king of Asia utters the decisive word even in the affairs of the Greek mother-country.

Here dissolution is going rapidly forward. Every power that has once more for a short time possessed some importance in Greece succumbs to it in turn; first Sparta, then Thebes and Athens. The attempts to establish permanent and assured conditions by local unions in small districts, as in Chalcidice under Olynthus, in Bœotia and Arcadia, were never able to hold out more than a short time. It was useless to look longer for the fulfilment of the national destiny. Feeble as the Persian kingdom was internally, every revolt against it, to say nothing of an attempt to make conquests and acquire a new field of colonisation in Asia,—the programme that Isocrates repeatedly urged upon the nation,—was made impossible by internal strife. Prosperity was ruined, the energy of the nation was exhausted in the wild feuds of brigands, the most desolate conditions prevailed in all communities. Greek history ends in chaos, in a hopeless struggle of all against all.

In this same period, to be sure, the positive, constructive criticism of Socrates and his school rose in opposition to the negative tendencies of sophistry; and made the attempt to put an end to the political misery, to create by a proper education the true citizen who looks only to the common welfare in place of the ignorant citizen of the existing states, who was governed only by self-interest. These efforts resulted in the development of science and the preservation for all future time of the highest achievements of the intellectual life of Hellas, but they could not produce an internal transformation of men and states, whose earthly life does not lie within the sphere of the problems of theoretical perception, but in that of the problems of will and power. So at the same time that Greek culture has reached the highest point of its development, prepared to become the culture of the world, the Greek nation is condemned to complete impotence.

For the development in the West, different as was its course, led to no other result. In the fifth century Greece controlled almost all Sicily except the western point, the whole south of Italy up to Tarentum, Elea and Posidonia and the coast of Campania. Nowhere was an enemy to be seen that might have become dangerous. The Carthaginians were repulsed, and the power of the Etruscans, who in the sixth century had striven for the hegemony in Italy, decayed, partly from internal weakness, partly in consequence of the revolt of their subjects, especially the Romans and the Sabines. The Cumæans under Aristodemus with the Sabines as their allies defeated Aruns, the son of Porsena of Clusium, at Aricia about 500 B.C., and in the year 474 the Etruscan sea power suffered defeat at Cumæ from the fleet of Hiero of Syracuse.

The cities of western Greece stood then as if founded for all eternity; they were adorned with splendid buildings, the gayest and most luxurious life developed in their streets; and they had leisure enough, after the Greek manner, to dissipate their energies, which were not claimed by external enemies, in internal strife and in struggles for the hegemony. Only the bold attempts which Phocæa made in the sixth century to turn the western basin of the Mediterranean likewise into a Greek sea, to get a firm footing in Corsica and southern Spain, had succumbed to the resistance of the Carthaginians, who were in alliance with the Etruscans. Only in the north, on the coast of Liguria from the Alps to the Pyrenees, Massalia maintained its independence. Southern Spain, Gades, and the coast of the land of Tarshish (Tartessus) were occupied by the Carthaginians about the middle of the fifth century; and the Greeks and all foreign mariners in general were cut off from the navigation of the ocean, as well as from the coasts of North Africa and Sardinia.

In the fourth century the political situation is totally changed in both east and west. The Greeks are reduced to the defensive and lose one position after the other. A few years after the destruction of the Athenian expedition the Carthaginians stretched out their hands for Sicily; in the years 409 and 406 they take and destroy Selinus, Himera, and Agrigentum; in the wars of the following years every other Greek city of the island except Syracuse was temporarily occupied and plundered by them.