These new armies could help states grow in size and became increasingly centralized. Early ancient armies continued to primarily use bows and spears, the same weapons that had been developed in prehistoric times for hunting. The findings at the site of Nataruk in Turkana, Kenya, have been interpreted as evidence of inter-group conflict and warfare in antiquity, but this interpretation has been challenged. Early armies in Egypt and China followed a similar pattern of using massed infantry armed with bows and spears. Infantry were at this time the dominant form of war, partially because the camel saddle and the stirrup were not yet invented. This infantry would be divided into ranged and shock, with shock infantry either charging to cause penetration of the enemy line or holding their own. These forces would ideally be combined, thus presenting your opponent with a dilemma: group your forces and leave them vulnerable to ranged, or spread them out and make them vulnerable to shock. This balance would eventually change as technology allowed for chariots, cavalry, and artillery to play an active role on the field.