Our third period embraces the supremacy of Athens from the end of the Persian to the end of the Peloponnesian war. It was the struggle with Xerxes which developed all the latent energies of the Greeks, which intensified their national existence, and which secured for Athens, as the central power on which the scattered forces of the race converged, the intellectual dictatorship of Hellas. No contest equals for interest and for importance this contest of the Greeks with the Persians. It was a struggle of spiritual energy against brute force, of liberty against oppression, of intellectual freedom against superstitious ignorance, of civilization against barbarism. The whole fate of humanity hung trembling in the scales at Marathon, at Salamis, at Platæa. On the one side were ranged the hordes of Asia--tribe after tribe, legion upon legion, myriad by myriad--under their generals and princes. On the other side stood forth a band of athletes, of Greek citizens, each one himself a prince and general. The countless masses of the herd-like Persian host were opposed to a handful of resolute men in whom the force of the spirit of the world was concentrated. The triumph of the Greeks was the triumph of the spirit, of the intellect of man, of light-dispersing darkness, of energy repelling a dead weight of matter. Other nations have shown a temper as heroic as the Greeks. The Dutch, for instance, in their resistance against Philip, or the Swiss in their antagonism to Burgundy and Austria. But in no other single instance has heroism been exerted on so large a scale, in such a fateful contest for the benefit of mankind at large. Had the Dutch, for example, been quelled by Spain, or the Swiss been crushed by the House of Hapsburg, the world could have survived the loss of these athletic nations. There were other mighty peoples who held the torch of liberty and of the spirit, and who were ready to carry it onward in the race. But if Persia had overwhelmed the Greeks upon the plains of Marathon or in the straits of Salamis, that torch of spiritual liberty would have been extinguished. There was no runner in the race to catch it up from the dying hands of Hellas, and to bear it forward for the future age. No; this contest of the Greeks with Persia was the one supreme battle of history; and to the triumph of the Greeks we owe whatever is most great and glorious in the subsequent achievements of the human race.