Memory

Milan Kundera wrote that "the struggle of man against power is the struggle of memory against forgetting." Citing the public and often obvious alteration of documents, photographs and history that took place in his home country of Czechslovakia during the Communist regime, Kundera makes the argument that reality and memory are malleable, capable of being changed irrevocably by those in power. His example is the elimination of the Czech Communist leader Clementis from a very public and historic photograph. While this story is placed within the context of a piece of fiction it is in fact based upon an actual event in history. The photograph of Clementis and Gottwald, with Gottwald wearing Clementis' fur cap, is a piece of historic fact. Also true is that, after his fall from grace, the Communist government cut Clementis from the photograph and denied that he had ever been in the photo, despite the hundreds of thousands of copies that had flooded the country several years before.
This terrifying power to change the nature of reality and memory lies within the grasp of any autocratic nation. Based solely on their control over the collective social consciousness, any government with the will can enforce their view of events of ideology upon the populace. During the Communist regime, Clementis stopped existing because the Communist government said it was so. Were it not for the memories of individual citizens who witnessed Clementis on the balcony with Gottwald, and the incontrovertible proof offered by undoctored photographs, history would have been changed, forced into line with the ruling government's concerns and goals.
In this sense, history is not an unbiased or empirical record of the past, but something that is shaped by those in power, something that can be formed and altered by those with the power to do so. The actions of social and political power within history are those of forgetfulness, striving to force the populace to selectively forget or incorrectly remember objectionable facts and events. Clementis was no longer in favor, he therefore had no place in either the current government or it's history.
Perhaps the most subversive act in a repressive society is the act of remembrance, the will to remember the truth and to speak that truth publically. It is the actions and memories of individuals that corrode the ability of those in power to alter the course of history to suit their needs.