This video explains the Incan Emperor Pachacuti (“The Earth Shaker”), who was able to successfully defend the city of Cusco from enemy attack in 1418, with him then forging Cusco into an Empire with the state taking its tax in labor rather than using money, where peasants were drafted as laborers.  Pachacuti was able to consolidate all of the previously independent kingdoms in the region through diplomacy and warfare.  Some of the practices of Pachacuti are explained, including his brutally killing generals who were successful in battles due to his being worried about his position as leader being taken by them.