Women's history is the study of the role that women have played in history and the methods required to do so. It includes the study of the history of the growth of woman's rights throughout recorded history, personal achievement over a period of time, the examination of individual and groups of women of historical significance, and the effect that historical events have had on women. Inherent in the study of women's history is the belief that more traditional recordings of history have minimized or ignored the contributions of women to different fields and the effect that historical events had on women as a whole; in this respect, women's history is often a form of historical revisionism, seeking to challenge or expand the traditional historical consensus. The main centers of scholarship have been the United States and Britain, where second-wave feminist historians, influenced by the new approaches promoted by social history, led the way. As activists in women's liberation, discussing and analyzing the oppression and inequalities they experienced as women, they believed it imperative to learn about the lives of their fore mothers—and found very little scholarship in print. History was written mainly by men and about men's activities in the public sphere, especially in Africa—war, politics, diplomacy and administration. Women are usually excluded and, when mentioned, are usually portrayed in sex-stereotypical roles such as wives, mothers, daughters, and mistresses. The study of history is value-laden in regard to what is considered historically "worthy." Other aspects of this area of study are the differences in women's lives caused by race, economic status, social status, and various other aspects of society.