The Ministry Of Truth
In George Orwell’s 1984 the Ministry of Truth was a government organization that was supposed to be focused on the pursuit of truth. The reality was that the Ministry of Truth was charged with erasing the truth of the past and replacing it with whatever lies the Party decides is best.
The concept of the Ministry of Truth recognizes that power is the most important commodity that the Party has access to. And the power over what people believe (which includes power over the past) is part of that equation.