While the author doesn't state that Kublai Khan was a Muslim, the passage is confusing because the list of notable harems is preceded by the reference to Islamic law and the number of wives and concubines allowed. I think that we should give the author some credit for doing his or her research, as well as the benefit of the doubt in this case. At any rate, neither King Tamba of Banaras (1100-1200 years before Islam) nor King Mongkut of Siam were Muslim either. As some readers have pointed out, Kublai Khan was not a Muslim either.