It is not as easy to understand the past as many who have written it would have us believe. The historians who look at it from the Protestant, progressive, 19th Century gentleman viewpoint are defined by Professor Butterfield as the Whig historians. The Whig historian studies the past with reference to the present. He looks for agency in history. And, in his search for origins and causes, he can easily select those facts that give support to his thesis and thus eliminate other facts equally important to the total picture.