Historians look at the events of the past through several different lenses in order to gain alternate perspectives on the historic events that lead to the present day. By examining the past through different historic disciplines, individual researchers are able to focus on specific areas and provide richer detail about the past. Then, the work from the separate disciplines is combined to give a complete picture of human history.
Military history is the study of examining the past of the world through the lens of armed combat. Combat between human groups is traceable back to the days of prehistoric society. Once humans formed into city-states and nations, combat became an even more important part of global history. International borders have been formed or destroyed as a result of military action. In recent memory, military history becomes extremely important for examining the current state of the world. Global involvement in the two World Wars is responsible for much of the current geopolitical landscape.
This field of study looks at the development of everything from local government to international relations. It examines the forms of government throughout history and their growth within a local and international framework. Activism, revolution and the evolution of various governmental processes are studied in political history. International relations are also important in the discipline. According to G.R. Elton, a professor of Constitutional History at Cambridge, the root of the field involves looking at how humans organize into groups and manage themselves as a group rather than as individual organisms.
Social history is a method of looking at society in all its forms throughout history. A society is simply a group of people who come together for some purpose, whether for the creation of families, for economic gains, for mutual protection, because of shared age, location or gender and so on. The study of social history is how social groups, small and large, have lived day-to-day lives throughout the past, and how events have shaped that daily life. How the daily life of a society influences global events is also important.
Religious history examines how global religions have shaped events in the portions of the world where they were prevalent. This is a good example of how the various historic disciplines overlap each other. A group of believers could be considered a society. By the same token, the rule over people is often tied to religion, such as when the king or queen of England also became the head of the Anglican church. By the same token, religion often plays a part in global conflict. Religious historians look at all these events from the basis of the events within the church that inspired them.