I think it becomes difficult because they all wanted to have more advantages than anyone else, that became too much for the country that they defeated. The Potsdam Conference became difficult because they have problems on the things that they should do with Germany that they want to completely disarm the country.
The North and the South had contrasting views on slave labor while the Federalists and Republicans fought on how much power the government should have. Each of these groups believed in America, and thought that their viewpoints would make it stronger. Their opinions began to contrast so much, that eventually a civil war broke out.
The Classical Period represented a consolidation of the basic elements of human civilization, thus overcoming our ancient nomadic lifestyle of hunting and gathering. The stablishment of ancient civilizations meant having the means to maintain a sedentary lifestlye, starting with agriculture and cattle raising. Then as cities grew more complex concepts became of everyday use, such as economy or religion.
The Classical Empires, such as Egypt, Mesopotamia, Persia, the Greek city-states, Carthage and Rome, expanded not only military power but economic growth, religion, language, the development of arts, technology and philosophy. These concepts started thousands of years ago, and became widespread because of the prosperity that sedentary lifestyle allowed in these empires, each one making its particular contribution to humanity.
Google is your best friend until you graduate from college.
