"Ahistorical Fantasias"

The Millions discussed an interesting trend in recent fiction (which I read about in Conversational Reading):

Now Matthew Sharpe, author of The Sleeping Father, has come along to toss his buckler into the ring. His new novel, published by Soft Skull, is called, simply Jamestown. I have not read it, but I can say that I like Sharpe's writing a lot. Here he reimagines the Jamestown colony as a postmodern battleground, pitting settlers who travel by bus against indigenous people unskilled in the use of sunscreen. This appears to be an "ahistorical fantasia," along the lines of Mark Binelli's Sacco and Vanzetti Must Die! or Chris Bachelder's U.S.! It's notable that younger American writers are fleeing the good government of the historical novel in an era that has itself started to seem dystopic...that has, as Frederic Jameson puts it, forgotten how "to think the present historically." But Sharpe's choice of setting seems propitious. For as the Vollmann and Barth books show, there's nothing novel about these wild new novels. They're part of a grand tradition of American craziness that, Jill Lepore points out, stretches back to John Smith himself - "Who told his glorious deeds to many, / But never was believ'd of any."

Sharpe used this term, "ahistorical fantasia," to describe his own work. Some digging in search engines tells me its been used before, but it's new to me and kind of intriguing: historical fiction that doesn't play by the rules.