There is no such thing as unbiased history. Historians can try to portray different sides to an issue, just like journalism. But thinking you can "get the truth" is naive. The closest you can get is the refuting lies.
Propaganda is made out to be different from journalism and history but the most efective propaganda is really hard to refute because it is based on facts. Any history book can be made into propaganda, because it is not a matter of truthfullness but of how it is used.