Most of the great changes in the world's history come about gradually and wise men can see them coming, for it is very hard to run counter to the nature of average men, and all great advances and degradations of society are the result of persistent causes; but a few times, since our records have been kept, there has arisen a single genius, who has done what no number of lesser men could accomplish, who has upset theories as well as dominions, preached a new faith, discovered some new application of Force which has given a fresh start to the world in its weary and perplexed struggle for a higher life. These few great men have so changed the current of affairs that we may safely say they have modified the future of the whole human race. At any rate they have taught us what might and dignity is attainable by man and has so given us ideals by which the commonest of us can estimate his worth and exalt his aspirations. So, too, there have been gigantic criminals and imperial fools who have wrecked the peace of the world and caused the "ape and tiger" elements, which were repressed by long and anxious struggles, to break out afresh in their savagery. His conquests were regarded as perfectly lawful, the world as his natural heritage, his will as a lawful testament. So, then, we may begin with him without much retrospect, and see what he founded and what he did for the advance of the world. The fragments of his Empire were great Empires in themselves and were the main channels of culture and civilization until the Roman Empire swallowed them up; and so far we will follow them, though even after their absorption they did not cease to affect history, and the capitals of the Alexandrian Empire were long the foremost cities in the Roman world. But this would take a far longer book, and more knowledge than any one man possesses, and must be set down in other books by other men. Even within the limits which are here laid down, thousands of details must be omitted, for the history of Eastern Europe and its wars in the century after Alexander is more complicated than can well be imagined and described. We must try to sever the wheat of important events from the chaff of raids and campaigns, and leave some distinct memories in the reader’s mind...