Fact or fiction contradiction

The blurb of the book I am reading at the moment includes the following text:

“A remarkable story of heroism and adventure, of a boy who had to become a man too soon…. He would become father to his people. He would be Genghis Khan”

Now, the last time I checked Genghis Khan was a real person – specifically the fearsome ruler of the Mongol Empire around the year 1200. So, I am rather puzzled than in the front pages of the book there is the following disclaimer:

“This novel is entirely a work of fiction. The names, characters and incidents in it are the work of the author’s imagination. Any resemblance to actual person, living or dead, events or localities is entirely coincidental”

So how does that work then? Am I expected to believe that it entirely coincidental that the author imagined a character who had the same name, and who took the same role in the same general location as a well-known historical character? I don’t think so. The disclaimer is wrong – the author’s just lucky that Genghis isn’t still alive to take appropriate action against him because from what I have read so far, it wouldn’t be pretty…