Emperor of China in the context of "Emperor Ping of Han"

China, officially the People's Republic of China (PRC), is a country in East Asia. With a population exceeding 1.4 billion, it is the second-most populous country after India, representing 17% of the world population. China borders fourteen countries by land across an area of 9.6 million square kilometers (3,700,000 sq mi), making it the third-largest country by area. The country is divided into 33 province-level divisions: 22 provinces, 5 autonomous regions, 4 municipalities, and 2 semi-autonomous special administrative regions. Beijing is the capital, while Shanghai is the most populous city by urban area and largest financial center.

China saw the first humans in the region arriving during the Paleolithic era. By the 2nd millennium BCE dynastic states had emerged in the Yellow River basin. The 8th–3rd centuries BCE saw a breakdown in the authority of the Zhou dynasty, accompanied by the emergence of administrative and military techniques, literature and philosophy. In 221 BCE, China was unified under an emperor, ushering in two millennia of imperial dynasties. With the invention of gunpowder and paper, the establishment of the Silk Road, and the Great Wall, Chinese culture flourished and has heavily influenced its neighbors and lands further afield. China began to cede parts of the country in the 19th century, to European powers by a series of unequal treaties. The 1911 Revolution overthrew the Qing dynasty and the Republic of China was established the following year. The country was unstable and fragmented during the Warlord Era, which ended upon the Northern Expedition conducted by the Kuomintang to reunify the country.

The Mandate of Heaven (Chinese: 天命; pinyin: Tiānmìng; Wade–Giles: T'ien-ming; lit. 'Heaven's command') is a Chinese political doctrine that was used in Ancient China and Imperial China to legitimize the rule of the king or emperor of China. According to this doctrine, Heaven (天, Tian) bestows its mandate on a virtuous ruler, called the Son of Heaven (天子, Tianzi), who is the supreme universal monarch that will rule the world (天下, Tianxia; "[all] under heaven"). If a ruler was overthrown, this was interpreted as an indication that the ruler and his dynasty were unworthy and had lost the Mandate. It was also a common belief that natural disasters such as famine and flood were divine retributions bearing signs of Heaven's displeasure with the ruler, so there would often be revolts following major disasters as the people saw these calamities as signs that the Mandate of Heaven had been withdrawn.

The Mandate of Heaven does not require a legitimate ruler to be of noble birth. Chinese dynasties such as the Han and Ming were founded by men of common origins, but they were seen as having succeeded because they had gained the Mandate of Heaven. Retaining the mandate is contingent on the just and able performance of the rulers and their heirs.

Emperor Wu of Han (156 – 29 March 87 BC), personal name Liu Che and courtesy name Tong, was the seventh emperor of the Han dynasty from 141 to 87 BC. His reign lasted 54 years – a record not broken until the reign of the Kangxi Emperor more than 1,800 years later – and remains the record for ethnic Han emperors. His reign resulted in a vast expansion of geopolitical influence for the Chinese civilization, and the development of a strong centralized state via governmental policies, economical reorganization and promotion of a hybrid Legalist–Confucian doctrine. In the field of historical social and cultural studies, Emperor Wu is known for his religious innovations and patronage of the poetic and musical arts, including the development of the Imperial Music Bureau into a prestigious entity. It was also during his reign that cultural contact with western Eurasia was greatly increased, directly and indirectly.

During his reign, Emperor Wu led the Han dynasty through its greatest territorial expansion. At its height, the Empire's borders spanned from the Fergana Valley in the west, to northern Korea in the east, and to northern Vietnam in the south. Emperor Wu successfully repelled the nomadic Xiongnu from systematically raiding northern China, and dispatched his envoy Zhang Qian into the Western Regions in 139 BC to seek an alliance with the Greater Yuezhi and Kangju, which resulted in further diplomatic missions to Central Asia. Although historical records do not describe him as being aware of Buddhism, emphasizing rather his interest in shamanism, the cultural exchanges that occurred as a consequence of these embassies suggest that he received Buddhist statues from Central Asia, as depicted in the murals found in the Mogao Caves.

Qin Shi Huang (Chinese: 秦始皇, Qín Shǐ Huáng, pronunciation; February 259 – 12 July 210 BC) was the founder of the Qin dynasty and the first emperor of China. Rather than maintain the title of "king" (wáng 王) borne by the previous Shang and Zhou rulers, he assumed the invented title of "emperor" (huángdì 皇帝), which would see continuous use by monarchs in China for the next two millennia.

Born in Handan, the capital of Zhao, as Ying Zheng (嬴政) or Zhao Zheng (趙政), his parents were King Zhuangxiang of Qin and Lady Zhao. The wealthy merchant Lü Buwei assisted him in succeeding his father as the king of Qin, after which he became King Zheng of Qin (秦王政). By 221 BC, he had conquered all the other warring states and unified all of China, and he ascended the throne as China's first emperor. During his reign, his generals greatly expanded the size of the Chinese state: campaigns south of Chu permanently added the Yue lands of Hunan and Guangdong to the Sinosphere, and campaigns in Inner Asia conquered the Ordos Plateau from the nomadic Xiongnu, although the Xiongnu later rallied under Modu Chanyu.

The Qin dynasty (/tʃɪn/ CHIN) was the first imperial dynasty of China. It is named for its progenitor state of Qin, a fief of the confederal Zhou dynasty (c. 1046–256 BC). Beginning in 230 BC, the Qin under King Ying Zheng engaged in a series of wars conquering each of the rival states that had previously pledged fealty to the Zhou. This culminated in 221 BC with the successful unification of China under Qin, which then assumed an imperial prerogative – with Ying Zheng declaring himself to be Qin Shi Huang, the first emperor of China, and bringing an end to the Warring States period (c. 475–221 BC). This state of affairs lasted until 206 BC, when the dynasty collapsed in the years following Qin Shi Huang's death. The Qin dynasty's 14-year existence was the shortest of any major dynasty in Chinese history, with only two emperors. However, the succeeding Han dynasty (202 BC – 220 AD) largely continued the military and administrative practices instituted by the Qin; as a result, the Qin have been credited as the originators of the Chinese imperial system that would endure in some form until the Xinhai Revolution in 1911.

Qin was a minor power for the first several centuries of its existence; its strength greatly increased in the 4th century BC, in large part owing to the administrative and military reforms of Shang Yang. They sought to create a strong, centralised state and a large army supported by a stable economy, which were developed in the Qin homeland and implemented across China following its unification. Reforms included the standardisation of currency, weights, measures, and the writing system, along with innovations in weaponry, transportation and military tactics.

The Chu–Han Contention (楚漢相爭), also known as the Chu–Han War (楚漢戰爭), was an interregnum of civil wars in Imperial China between the fall of the Qin dynasty in 206 BCE and the establishment of the Han dynasty in 202 BCE.

After the Qin dynasty was overthrown, the empire was divided into the Eighteen Kingdoms ruled by enfeoffed rebel leaders and surrendered Qin generals according to arrangement by Xiang Yu, the hegemon warlord. Due to dissatisfaction among the rebels, wars and rebellions soon broke out, most prominently between two major powers – Xiang Yu and Liu Bang, who were the rulers of the Western Chu and Han kingdoms, respectively. Other kingdoms also waged war against Chu and Han and among themselves, but these were largely insignificant compared to the Chu-Han conflict. The wars ended with a total victory to Liu Bang at the Battle of Gaixia, during which Xiang Yu committed suicide after losing all his men in a last stand. Having subdued all rival contenders, Liu Bang subsequently proclaimed himself emperor of the newly established Han dynasty.

Wang Mang (45 BC – 6 October AD 23), courtesy name Jujun, officially titled the Shijianguo Emperor, was the founder and the only emperor of the short-lived Xin dynasty of imperial China. Originally an official and consort kin of the Han dynasty, Wang seized the throne in AD 9. The Han dynasty was restored after his overthrow, and his rule marked the separation between the earlier Western Han dynasty and the later Eastern Han dynasty.

Traditional Chinese historiography viewed Wang as a tyrant and usurper, while more recently some historians have portrayed him as a visionary and selfless social reformer. During his reign, he abolished slavery and initiated a land redistribution program. A learned Confucian scholar who sought to implement the harmonious society he saw in the Chinese classics, his efforts ended in chaos. Wang Mang's late reign saw large-scale peasant rebellions, most notably the revolts of the Lülin and Red Eyebrows (Chimei). In October AD 23, the capital Chang'an was overrun and the imperial palaces sacked. Wang Mang was killed in the battle. The Han dynasty was re-established, the Gengshi Emperor taking the throne in the year 23 and the Guangwu Emperor taking the throne in the year 25 after defeating the Red Eyebrows who had deposed the Gengshi Emperor.

The emperors of the Han dynasty were the supreme heads of government during the second imperial dynasty of China; the Han dynasty (202 BC – 220 AD) followed the Qin dynasty (221–206 BC) and preceded the Three Kingdoms (220–265 AD). The era is conventionally periodised into the Western Han (202 BC – 9 AD) and Eastern Han (25–220 AD).

The Han dynasty was founded by the peasant rebel leader Liu Bang, known posthumously as Emperor Gao (r. 202–195 BC). The longest reigning emperor of the dynasty was Emperor Wu (r. 141–87 BC), who reigned for 54 years. The dynasty was briefly interrupted by the Xin dynasty of the former regent Wang Mang, but he was killed during a rebellion on 6 October 23 AD. The Han dynasty was reestablished by Liu Xiu, known posthumously as Emperor Guangwu (r. 25–57 AD) or Guangwu Di, who claimed the throne on 5 August 25 AD. The last Han emperor, Emperor Xian (r. 189–220 AD), was a puppet monarch of Chancellor Cao Cao (155–220 AD), who dominated the court and was made King of Wei. On 11 December 220, Cao's son Pi usurped the throne as Emperor Wen of Wei (r. 220–226 AD) and ended the Han dynasty.

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.

The Han dynasty (202 BC – 220 AD) was the second imperial dynasty of China, following the Qin dynasty (221–207 BC). It was divided into the periods of Western (Former) Han (202 BC – 9 AD) and Eastern (Later) Han (25–220 AD), briefly interrupted by the Xin dynasty (9–23 AD) of Wang Mang. The capital of Western Han was Chang'an, and the capital of Eastern Han was Luoyang. The emperor headed the government, promulgating all written laws, serving as commander-in-chief of the armed forces, and presiding as the chief executive official. He appointed all government officials who earned a salary of 600 bushels of grain or more (though these salaries were largely paid in coin cash) with the help of advisors who reviewed each nominee. The empress dowager could either be the emperor's actual or symbolic mother, and was in practice more respected than the emperor, as she could override his decisions; she could even make decisions on behalf of the emperor in dilemma matters of the country or for the order and continuation of the dynasty. If necessary, with the support of the courtiers, she would decide on his successor or his dismissal, although such a challenge was only raised by the empress dowager to the emperor during the emperor's youth or incapacity. The emperor's executive powers could also be practiced by any official upon whom he bestowed the Staff of Authority. These powers included the right to execute criminals without the imperial court's permission.

Near the beginning of the dynasty, semi-autonomous regional kings rivaled the emperor's authority. This autonomy was greatly diminished when the imperial court enacted reforms following the threats to central control like the Rebellion of the Seven States. The end of the Han dynasty came about during a time of civil, military and religious upheaval, which resulted in the period of Three Kingdoms.