Axial Age
Beginning in the 8th century BCE, the "Axial Age" saw the development of a set of transformative philosophical and religious ideas, mostly independently, in many different places. Chinese Confucianism, Indian Buddhism and Jainism, and Jewish monotheism are all claimed by some scholars to have developed in the 6th century BCE. (Karl Jaspers' Axial-Age theory also includes Persian Zoroastrianism, but other scholars dispute his timeline for Zoroastrianism.) In the 5th century BCE, Socrates and Plato made substantial advances in the development of ancient Greek philosophy.