"History is written by the victors." —Winston Churchill
You have the power to get history right or wrong. Bernard Bailyn, winner of the 2012 Ruth Ratner Miller Memorial Award in American History, commented about the limitations that exist for historians. His example is the historical view of the birth of the Constitution. Bailyn points out that historians describe the events that lead to the writing of the Constitution with such reverence that they do not include the accidental nature of the entire event. For instance, Massachusetts was debating whether or not to sign. Supporters of the Constitution promised John Hancock, who was sick with gout, a run at the presidency if he spoke at the convention. Bailyn's point is that there were many accidents and uncertainties during the writing of the Constitution. Historians who do not recount the events as they actually played out—they often show some bias.
Ideally, historians don't bring their personal bias into their work. It is their job to research and interpret manuscripts, interviews, photographs, artifacts, and books, and to present the results of that research in a clear, straightforward, impartial manner. They have the power to omit any information, which may result in people getting the wrong impression of history. While historians are not under the same guidelines as saints, people often trust their evidence and research. Abuse this power and an historian may, unfortunately, change our view of history. For all we know, that cow who started the Chicago Fire was a total patsy.