Sentence:  However, they encounter a serious problem: the actor begins to alter the dates of verifiable historical events, moving the Tunguska explosion from 1888 to 1908. We are told that, from this point on, 'the film project foundered further into a chaos of <WSD>unhistory</WSD>' (1983, 56). 
Meaning of the word marked with <WSD> tags:  Inaccurate representations of the past that are presented as history.