Genghis: Lords of the Bow (Conqueror Series, Bk. 2)

His warriors only have the bow, the horse and an iron discipline born from a land of ice, hunger and death. Genghis Khan, the greatest of the warriors, must unite the most warlike tribes on earth in order to forge a new nation from the wild plains and mountains of Mongolia. To achieve this, he must break the ancient enemy who has kept his people divided; he must attack them in their fortresses and walled cities; he must find a new way of warfare, while at the same time coping with his restless generals, ambitious brothers and growing sons.