Here an interesting video. About it:

Has history been tampered with? We shall never know just how many historical documents are in fact counterfeit. History in general goes hand in hand with the history of forgeries; countless chronicles as well as works of art and literature have been considered authentic for centuries before becoming denounced as counterfeit.

A presumed fragment of Cicero's "De Consolatione" discovered by the famous humanist scholar Sigonius only became identified as a work of the latter two centuries after the death of the author -- we would probably still believe in Cicero's authorship of said fragment if it hadn't been for the discovery of Sigonius' written confession.

Similar examples are rather abundant -- the "Thespian poet Lucius Varus" who turned out to be a 18th century Dutch scientist by the name of Heerkens plagiarizing from the 16th century Venetian author Corrario, the German "translation" of a Phoenician history tractate by a student named Wagenfeld in the 19th century, "classical" texts sold to the Leipzig library by a certain Schennis in the 1920's and so forth. Think of just how many remain undiscovered -- after all, the larger part of the iceberg always remains underwater.

However, there may be an equal amount of valid historical documents in existence that were declared forgeries due to their being at odds with the official history. Anatoly Fomenko, the prominent mathematician, was the first to apply natural scientific methods to historical data, coming up with a revolutionary theory which implies a radical revision of history as we know it. This theory finally explains such historical oddities as the existence of Christian tabernacles in the pagan town of Pompeii and the Ottoman Turks referred to as "Persians" in mediaeval documents. It is rendered in Fomenko's fundamental work entitled: "History: Fiction or Science" which is finally out in English. "Sensational" is a very mild term -- this book is heretical, controversial and clearly subversive -- but even the most uncanny ideas it contains are all backed up by statistics, astronomy, and brilliant logic. Fomenko's book may infuriate you since it contradicts everything you were taught in school, but once you're through with it, your view of history shall never be the same again!

Dan Brown beats Martin Luther with "Da Vinci code"

Popular fiction dealing with conspiracies of one sort or another is actually quite tame as compared to reality. Dan Brown pens a possible conspiracy of the church against the memory of its originator Jesus. He follows unknowingly in the steps of Martin Luther who started his protestant revolution with accusation of Papal conspiracy in the matter of Constantine's testament, take good note that Martin Luther was right and the testament was false . Well he had as media outlet nothing better than the doors of the Wittenberg's cathedral. Dan Brown has mass media at his disposal. The Roman Catholic Church, for instance, is involved in a much greater hoax than the most daring writer could possibly conceive of - one that deals with the very foundations of history itself. The above statement is neither an exaggeration, nor a metaphor - very few people are aware that the B C A D chronology as we know it was created by a handful of Jesuits in the 16th 17th century - Joseph Scaliger, Dionysius Petavius and their successors. We have grown so accustomed to a timeline that runs through many millennia, from the Egyptian pyramids to the present day, that the mere thought of questioning its veracity seems perfectly preposterous - just like the notion of a rotating earth must have seemed in the epoch of Galileo Galilei, and just as heretical. But nevertheless - the entire conception of ancient and mediaeval history know to us today owes its existence to a XVI century Jesuit hoax. A hoax that has finally been exposed with the aid of astronomy, mathematical statistics and modern computational facilities by one of the world's leading mathematicians - the Russian Academician A. T. Fomenko. His fundamental work on chronology, now available in English, is more fascinating than Dan Brown at his wildest. Yet it is truly a non-fiction work - that goes to say, everything else you have read about history should probably classify as fiction. And, let's face it, much duller fiction than "The Da Vinci Code" barnburner.
The video:

Has history been tampered with?