Dong Zhongshu in the context of "Western Han dynasty"

The Han dynasty was an imperial dynasty of China (202 BC – 9 AD, 25–220 AD) established by Liu Bang and ruled by the House of Liu. The dynasty was preceded by the short-lived Qin dynasty (221–206 BC) and a warring interregnum known as the Chu–Han Contention (206–202 BC), and it was succeeded by the Three Kingdoms period (220–280 AD). The dynasty was briefly interrupted by the Xin dynasty (9–23 AD) established by the usurping regent Wang Mang, and is thus separated into two periods—the Western Han (202 BC – 9 AD) and the Eastern Han (25–220 AD). Spanning over four centuries, the Han dynasty is considered a golden age in Chinese history, and had a permanent impact on Chinese identity in later periods. The majority ethnic group of modern China refer to themselves as the "Han people" or "Han Chinese". The spoken Chinese and written Chinese are referred to respectively as the "Han language" and "Han characters".

The Han emperor was at the pinnacle of Han society and culture. He presided over the Han government but shared power with both the nobility and the appointed ministers who came largely from the scholarly gentry class. The Han Empire was divided into areas directly controlled by the central government called commanderies, as well as a number of semi-autonomous kingdoms. These kingdoms gradually lost all vestiges of their independence, particularly following the Rebellion of the Seven States. From the reign of Emperor Wu (r. 141–87 BC) onward, the Chinese court officially sponsored Confucianism in education and court politics, synthesized with the cosmology of later scholars such as Dong Zhongshu.

The Han dynasty (202 BCE – 220 CE) was a period of Imperial China divided into the Western Han (202 BCE – 9 CE) and Eastern Han (25–220 CE) periods, when the capital cities were located at Chang'an and Luoyang, respectively. It was founded by Emperor Gaozu of Han and briefly interrupted by the regime of Wang Mang (r. 9–23 CE) who usurped the throne from a child Han emperor.

The Han dynasty was an age of great economic, technological, cultural, and social progress in China. Its society was governed by an emperor who shared power with an official bureaucracy and semi-feudal nobility. Its laws, customs, literature, and education were largely guided by the philosophy and ethical system of Confucianism, yet the influence of Legalism and Daoism (from the previous Zhou dynasty) could still be seen. Members of the scholarly-gentry class who aspired to hold public office were required to receive a Confucian-based education. A new synthetic ideology of Han Confucianism was created when the scholar Dong Zhongshu (179–104 BCE) united the Confucian canon allegedly edited by Kongzi, or Confucius (551–479 BCE), with cosmological cycles of yin and yang and the Chinese five elements.