Ничего подобного. Всё, что формально требуется для написания исторического романа - написать роман о прошлом и не на основании личного опыта. Споры идут только о том, какой период можно отсчитывать назад:
Definitions differ as to what constitutes a historical novel. On the one hand The Historical Novel Society defines the genre as works "written at least fifty years after the events described",[2] whilst on the other hand critic Sarah Johnson delineates such novels as "set before the middle of the last [20th] century […] in which the author is writing from research rather than personal experience."[3] Then again Lynda Adamson, in her preface to the bibliographic reference work World Historical Fiction, states that while a "generally accepted definition" for the historical novel is a novel "about a time period at least 25 years before it was written", she also suggests that some people read novels written in the past, like those of Jane Austen (1775–1817), as if they were historical novels.[4]