Conqueror (Conqueror #5) by Conn Iggulden

A scholar who conquered an empire larger than those of Alexander or Caesar. A warrior who would rule a fifth of the world with strength and wisdom. A man who betrayed a brother to protect a nation. From a young scholar to one of history's most powerful warriors, Conqueror tells the story of Kublai Khan - an extraordinary man who should be remembered alongside Julius Caesar, Alexander the Great and Napoleon Bonaparte as one of the greatest conquerors the world has ever known.