George Orwell on controlling history

I think you're just making an assertion without any argumentation here. How has the historiography of past actually distorted our understanding of history and how and when we became aware of it? Through the "ideological lens" of modern academic research, it's actually the "Enlightenment" or "whig" view of history that has distorted our understanding, especially with regards to the history of science.

Concrete examples are numerous: Draper/White-thesis in history of science (here's a good web resource: http://www.asa3.org/ASA/PSCF/1987/PSCF9-87Lindberg.html), Edward Gibbon's History of the Fall and Decline of Roman empire and Gottfried Christian Voigt's "nine million witches burnt" come to mind, just to give you some major examples of Enlightenment writing of history. They all have been very influential and popular, but none of them are taken seriously anymore by contemporary scholarly consensus. It may come as a surprise to you, but cherry-picking and distortion of historical facts is not a privilege of the bad religious guys only.

Nobody who has written about history over a hundred years ago cannot be taken seriously anymore, as we just have so much more in formation than they had: most of all we have more information on the effects of Christianity that we did not have in time of Christian overlordship in the Europe.

I doubt there ever were any "hordes of Christian historians" who systematically forgot all the unpleasant facts. As we know, historiography became an independent discipline AFTER the time of Christian overlordship in Europe, namely in the 18th and 19th centuries. The main occupation of the historians during those times was not to correct the errors of earlier records but to create those records, as there were very few to start with. That's why your accusations of bias and distortion are so silly.

I'm still wondering: what unpleasant facts Christian historians excluded from their writings? I've never heard anyone make this accusation before so it intrigues me. And i'd like some of evidence too. As i said, historiography as a distinct discipline dates to the Enlightenment era and the prominent historians then, like Gibbon, Voltaire and Hume can hardly be accused of Christian bias.

The decline of pagan religions and philosophies during that time has, to my knowledge, never been denied, not by any Christian author anyway; on the contrary, Christian historians are our main sources about those events. For an example, the destruction of Alexandrian temples was recorded by church historian Socrates of Constantinople and the murder of Hypatia by a Christian mob was documented by bishop John of Nikiû.

I still have no idea what Christian historians you're talking about. As I said, the point is that things you mention (e.g. persecution of pagans by Theodosius I) were documented by Greek church historians (such as aforementioned Socrates of Constantinople). Contrary to what you claim, they didn't deny or conceal those facts. FYI, I'm a history major at a secular university and my faculty is religiously unaffiliated.