I don't think I'm necroing this thread as it is still pretty active by History Forum standards. What I believe is the basic cause (in ambigious terms) of most great empires in history is comparative advantages. Whenever a country has gained some significant economic, military or leadership advantages and has had a government with the will to exploit that expansion has begun. The fall is then later caused by the loss of those advantages and the overstretch of the empire, or even the development of disadvantages (too little innovation).
Actually, I think this still applies in the world. Achievements of countries are no longer measured by territorial gains, but rather by differences in standards of living and general economic strengths. Consider a nation such as the US: Why is it deemed to be so powerful? Well, 1) it has a high standard of living, and 2) big economic resources (high population multiplied by a high average income).
The analysis for what caused the fall of the western empire is very interesting as I believe it is central the general study of the subject of the rise of nations.
Actually, I think this still applies in the world. Achievements of countries are no longer measured by territorial gains, but rather by differences in standards of living and general economic strengths. Consider a nation such as the US: Why is it deemed to be so powerful? Well, 1) it has a high standard of living, and 2) big economic resources (high population multiplied by a high average income).
The analysis for what caused the fall of the western empire is very interesting as I believe it is central the general study of the subject of the rise of nations.