Ancient world history can often seem a blur of civilizations and peoples, rising and falling.  We do have to remember that we are looking at a very long period of time in a very short period of time, and that years then were just as long as years are today!  But Robert Wright wrote "if we relax our vision, and let these details go fuzzy, then a larger picture comes into focus:  As the centuries fly by, civilizatoins may come and go, but civilization flourishes, growing in scope and complexity."  [Robert Wright, Nonzero: The Logic of Human Destiny, New York, 2000, p. 108.]