Given these gaps and contradictions, this novel has opted for a lucid story line that is not inconsistent with key known facts and in no way violates the historical record,
Unless you count Baudouin and Sibylle suffering spontaneous amnesia about their relationship to the count of Flanders, of course. Which is really weird, since Sibylle was probably named after the count of Flanders’ mother (and her half-aunt), Sibylle d’Anjou.

