The thesis statement is the sentence or group of sentences that presents the main idea, or the focus, of your paper. It is a claim or contention in need of explanation, support, or development — a position about the past that readers are unlikely to accept without a good argument on your part. As Charles Darwin observed: “. . . all observation must be for or against some view, if it is to be of any service.” You may begin your research with a preliminary hypothesis or educated guess. Use your hypothesis as a guide, but do not allow it to lead you astray. If your research does not support your hypothesis, be prepared to alter your hypothesis. As you alter and change your hypothesis based on the facts you find, you are formulating a thesis based on your interpretation of the facts. This is what history is all about.