Greece learned too late the art of combining for self-defence. In the war against the vast power of Persia, Athens stood almost alone. What aid she got from the rest of Greece was given grudgingly. Themistocles had to gain the aid of the Grecian fleet at Salamis by a trick. Philip of Macedonia conquered Greece by dividing it and fighting it piecemeal. Only after the close of the Macedonian power and the beginning of that of Rome did Greece begin to learn the art of unity, and then the lesson came too late. The Achaean League, which combined the nations of the Peloponnesus into a federal republic, was in its early days kept busy in forcing its members to remain true to their pledge. If it had survived for a century it would probably have brought all Greece into the League, and have produced a nation capable of self-defence. But Rome already had her hand on the throat of Greece, and political wisdom came to that land too late to avail. [Illustration: REMAINS OF THE TEMPLE OF MINERVA, CORINTH.] We have come, indeed, to the end of the story of Grecian liberty. Twice Greece rose in arms against the power of Rome, but in the end she fell hopelessly into the fetters forged for the world by that lord of conquest. Of the celebrated cities of Greece two had already fallen. Thebes had been swept from the face of the earth in the wind of Alexander's wrath. Sparta had been reduced to a feeble village by the anger of Philopoemen. Corinth, now the largest and richest city of Greece, was to be razed to the ground for daring to defy Rome; and Athens was to be plundered and humiliated by a conquering Roman army. It will not take long to tell how all this came about. The story is a short one, but full of vital consequences. Philopoemen, the great general of the Achaean League, died of poison 183 B.C. In the same year died in exile Hannibal, the greatest foe Rome ever knew, and Scipio, one of its ablest generals. Rome was already master of Greece. But the Roman senate feared trouble from the growth of the Achaean League, and, to weaken it, took a thousand of its noblest citizens, under various charges, and sent them as hostages to Rome. Among them was the celebrated historian Polybius, who wrote the history of Hannibal's wars. These exiles were not brought to trial on the weak charges made against them, but they were detained in Italy for seventeen years. By the end of that time many of them had died, and Rome at last did what it was not in the habit of doing, it took pity on those who were left and let them return home.