The Spring and Autumn Period, from 770 to 476 BCE, and the Warring States Period, from 475 to 221 BCE, were two of the most important eras in Chinese history. These periods began with the decline of the Zhou Dynasty's central authority and ended with the Qin Dynasty's unification of China. During these centuries, numerous independent states competed for power, leading to significant developments in politics, philosophy, military strategy, and culture that would shape Chinese civilization for millennia to come.