How is one to understand world history considered as the history of humanity? This is not an easy question to answer, especially given the extraordinary variety of conditions under which human beings live. The reality of cultural diversity would appear to make the task of someone constructing a general history of humanity rather daunting. Yet there is also a great variety in the languages created by human groups, and it is possible to group these languages into families. It has also been the normal practice of historians to group together human units into a number of entities - these include societies, cultures, civilizations and political units such as states that have things in common, and which effectively become the actors of world history. Human history can then be conceptualized as the interaction among such actors, and these interactions can take a number of forms ranging from peaceful trade and the interchange of ideas to war and extermination. It is clear, however, that when we use a term such as 'the state' we are looking at human entities in a different way from when we use the term 'society'. We assume that states, as actors, will interact differently than do societies. States interact as political entities conducting diplomacy and war while social interaction can range from intermarriage to the copying of customs, including dress, diet and social practices.