History is the study of change over time, and it covers all aspects of human society. Political, social, economic, scientific, technological, medical, cultural, intellectual, religious and military developments are all part of history

A historian is a person who studies and writes about the past and is regarded as an authority on it. Historians are concerned with the continuous, methodical narrative and research of past events as relating to the human race; as well as the study of all history in time.