The Warring States period in Chinese history comprises the final centuries of the Zhou dynasty, which were characterized by warfare, bureaucratic and military reform, and political consolidation. It followed the Spring and Autumn period and concluded with the wars of conquest that saw the state of Qin annex each of the other contender states by 221 BC and found the Qin dynasty, the first imperial dynastic state in East Asian history. It saw developments in philosophy, commerce, agriculture, the arts, and society at large.