But, as usual, there were jealousies. Athens did at length combine with Thebes to oppose Philip, but by that time he had found allies in Greece itself. He marched south, met the Thebans and Athenians at Chæronea, in 338 B.C., and won a battle which makes a very great difference in our story, for it was so decisive that it practically put an end, once for all, to the independence of Greece. Greece for many years had to {155} do what Macedonia ordered. Philip was given, or assumed, command of all the Greek armies, with a title which has been translated "Captain-General." Commander-in-Chief might describe it nearly as well, and is a title better known to us. And now, for the first time, we have a really united Greece. But though a united Greece, it was not a free Greece. It was united because it was under the masterful rule of the Macedonians. But, being united, and joined moreover with the forces of the Macedonians and their allies it probably was the greatest fighting force the world had yet known. There was one direction in particular in which it was likely that it would make its force felt--against Persia. [Sidenote: Alexander the Great] In the midst of the preparation for the invasion of the Persian empire, Philip was assassinated, after reigning for twenty-three years, and was succeeded by his son Alexander--Alexander the Great--then only twenty years old. And Alexander the Great died only twelve years later. He was therefore only thirty-two years old at his death. Yet he had time to win the name of Great; and when you hear his story you will think that it was well deserved, for the story is extraordinary. It is extraordinary by reason of the immense extent of territory over which Alexander went victoriously and with marvellous rapidity. But the explanation is not very far to seek--it lies in that very powerful army and fighting machine which had been delivered to him by his father; in that, and in the lack of resisting power in the enemies whom it overcame, is the explanation of his success. The fighting power of the Persian empire had spent itself; and partly it had spent itself in the destruction {156} of the fighting power of the nations with which it had come into touch. In that, as it seems, taken together with the very real strength of Alexander's army, lies the explanation. The Persian power, moreover, apart from its loss in actual fighting, had probably lost much by life in conditions more easy and pleasant than those in the more rugged and barren country from which Cyrus had led the Persians. We have noticed the same change in the character of conquering nations already, and may see it yet again in course of the great story. As for this particular story which we are telling at the moment, about Alexander and the march of his ever-victorious army, it will be a short story although such a marvellous one. It is short, just because the march had scarcely a stopping-place, scarcely a check, all through.