During the Han Dynasty, China officially became a state and prospered domestically: agriculture, handicrafts and commerce flourished, and the population reached over 55 million people. Meanwhile, the empire extended its political,, and territory over Korea, Mongolia, Vietnam, and Central Asia before it finally collapsed under a combination of domestic and external pressures. It also had a series of military outposts in some of these regions, including Central Asia, Mongolia, and Persia.
The first of the two periods of the dynasty was the Former Han Dynasty or Western Han Dynasty 206 BCE?, seated at Chang'an. The Later Han Dynasty or Eastern Han Dynasty 25?220 CE was seated at Luoyang. The western-eastern Han convention is currently used to avoid confusion with the Later Han Dynasty of the Period of the Five Dynasties and the Ten Kingdoms although the former-later nomenclature was used in history texts including Sima Guang's ''Zizhi Tongjian''.
The Han Dynasty was notable also for its military prowess. The empire expanded westward to the Tarim Basin , with military expeditions as far west as beyond the Caspian Sea, making possible a relatively safe and secure caravan and mercantile traffic across Central Asia. The paths of caravan traffic came to be known as the "Silk Road" because the route was used to export Chinese silk. Chinese armies also invaded and annexed parts of northern Korea and northern Vietnam toward the end of the 2nd century BC. The borders near the peripheral territories were often tense with possible conflict with other states. To ensure peace with non-Chinese powers, the Han court developed a mutually beneficial "tributary system". Non-Chinese states were allowed to remain autonomous in exchange for symbolic acceptance of Han overlordship. Tributary ties were confirmed and strengthened through intermarriages at the ruling level and periodic exchanges of gifts and goods.
Within the first three months after Qin Dynasty Qin Shi Huang's death at Shaqiu, widespread revolts by peasants, prisoners, soldiers and descendants of the nobles of the sprang up all over China. Chen Sheng and Wu Guang, two in a group of about 900 soldiers assigned to defend against the Xiongnu, were the leaders of the first rebellion. Continuous finally toppled the Qin dynasty in 206 BC. The leader of the insurgents was Xiang Yu, an outstanding military commander without political expertise, who divided the country into 19 feudal states to his own satisfaction.
The ensuing war among those states signified the five years of Chu Han Contention with Liu Bang, the first emperor of the Han Dynasty, as the eventual winner with the help of and Han Xin. Initially, "Han" consisted merely of modern Sichuan, Chongqing, and southern Shaanxi and was a minor humble principality, but eventually grew into an empire; the Han Dynasty was named after the principality, which was itself named after Hanzhong —modern southern Shaanxi, the region centering the modern city of Hanzhong. The beginning of the Han Dynasty can be dated either from 206 BC when the Qin dynasty crumbled and the Principality of Han was established or 202 BC when Xiang Yu committed suicide.
Taoism and feudal system
The new empire retained much of the Qin administrative structure, but retreated somewhat from centralized rule by establishing vassal principalities in some areas for the sake of political convenience. After the establishment of the Han Dynasty, Emperor Gao divided the country into several "feudal states" to satisfy some of his wartime allies, though he planned to get rid of them once he had consolidated his power.
After his death, his successors from to tried to rule China combining methods with the philosophic ideals. During this "pseudo-Taoism era", a stable centralized government over China was established through revival of the agriculture sectors and fragmentations of "feudal states" after the suppression of the Rebellion of the seven states.
Emperor Wu and Confucianism
During the "''Taoism era''", China was able to maintain peace with Xiongnu by paying tribute and marrying princesses to them. During this time, the dynasty's goal was to relieve the society of harsh laws, wars, and conditions from both the Qin Dynasty, external threats from nomads, and early internal conflicts within the Han court. The government reduced taxation and assumed a subservient status to neighboring nomadic tribes. During this era, the government reduced its role in civilian lives and initiating a period of stability known as the ''Rule of Wen and Jing'' , named after the two Emperors of this particular era. However, under , who reigned over one of the most prosperous periods of the Han Dynasty, the Empire was able to reassert its power. At its height, Han China incorporated present day Qinghai, Gansu, and northern Vietnam into its territories. The state mounted military expeditions into Siberian lands beyond Lake Baikal in the northern extremities and established military bases on the shores of the Caspian Sea at its western extremity.
Emperor Wu decided that Taoism was no longer suitable for China and officially declared it a Confucian state; however, like the Emperors of China before him, he combined methods with the ideal. This official adoption of Confucianism led not only to a civil service nomination system, but also compulsory knowledge of Confucian classics among candidates for the imperial bureaucracy, a requirement that lasted up to the establishment of the Republic of China in 1911. Confucian scholars gained prominent status as the core of the civil service.
The bureaucratic system of the Han Dynasty can be divided into two systems, the central and the local. As for the central bureaucrats in the capital, it was organized into a head cabinet of officials called the Three Lords and Nine Ministers . This cabinet was led by the , who was included as one of the . Officials were graded by rank and salary, were appointed to posts based on the merit of their skills rather than aristocratic clan affiliation, and were subject to dismissal, demotion, and transfer to different administrative regions. The local official during the former Han Dynasty was different from that of the later Han Dynasty. As for the former Han, there were two administered levels, the county and the ''xian'' . In the former Han Dynasty the ''xian'' was a subdivision or sub-prefecture of a county. During the Han period, there were about 1,180 of these xian, or sub-prefectures. The entire Han Empire was heavily dependent upon its county governors , as they could decide military policy, economic regulations, and legal matters in the county they presided over. According to historians Ebrey, Walthall, and Palais:
The main tax exacted on the population during Han times was a poll tax, fixed at a rate of 120 government-issued coins for adults.For adults there was also the addition of mandatory labor service for one month out of the year. Besides the poll tax, there was also the administered by county and commandery officials. This was set by the government at a relatively low rate of one-thirtieth of the collected harvest.
With a large amount of revenue in stable times, the Han government was able to fund various public works projects and state infrustructure. In the year 3 CE, a formalized nationwide government school system was established under Emperor Ping of Han, with a central school located in the capital Chang'an and local schools in the prefectures and counties.
As a result of the recorded debate ''The Discourses on Salt and Iron'' about state control over non-renewable resources in China, the state decided to impose government on salt and iron in the 1st century BC. The government monopoly on salt remained a distinctive feature of the Chinese bureaucracy in subsequent dynasties, although it fell out of use at certain times when merchants were allowed to mine it, refine it, and sell it in free trade.
Culture, society, and technology
The intellectual, literary, and artistic endeavors revived and flourished during the Han Dynasty. The Han period produced by birth China's most famous historian, Sima Qian , whose ''Records of the Grand Historian'' provides a detailed chronicle from the time of legendary emperor to that of the . Technological advances also marked this period. One of the great Chinese inventions, paper, dates from the Han Dynasty, largely attributed to the court eunuch Cai Lun . By the 1st century BC, the Chinese had discovered how to forge the highly durable metal of steel, by melting together wrought iron with cast iron. There were great mathematicians, astronomers, statesmen, and technological inventors such as Zhang Heng , who invented the world's first hydraulic-powered armillary sphere. He was also largely responsible for the early development of the style in China. Zhang Heng's work in mechanical gear systems influenced countless numbers of inventors and engineers to follow, such as Ma Jun, Yi Xing, Zhang Sixun, Su Song, etc. Zhang Heng's most famous invention was a seismometer with a swinging pendulum that signified the cardinal direction of earthquakes that struck locations hundreds of kilometres away from the positioned device. There was also continuing development in Chinese philosophy, with figures such as Wang Chong , whose written work represented in part the great intellectual atmosphere of the day. Among his various written achievements, Wang Chong accurately described the water cycle in meteorology. Zhang Heng argued that light emanating from the moon was merely the reflected light that came originally from the sun, and accurately described the reasons for solar eclipse and lunar eclipse as path obstructions of light by the celestial bodies of the earth, sun, and moon.
Military technology in the Han period was advanced by the use of cast iron and steel, which the 1st century engineer Du Shi had made easier by applying the hydraulic power of waterwheels in working the bellows of the blast furnace. The military of the Han Dynasty also engaged in chemical warfare, as written in the ''Hou Han Shu'' for the governor of Ling-ling, Yang Xuan, who fought against a peasant revolt near Guiyang in 178 AD:
There were other notable technological advancements during the Han period. This includes the hydraulic-powered trip hammer for agriculture and iron industry, the winnowing machine for agriculture, and the rotary and of Ding Huan .
Beginning of the Silk Road
From 138 BC, Emperor Wu also dispatched Zhang Qian twice as his envoy to the Western Regions, and in the process pioneered the route known as the Silk Road from Chang'an , through Xinjiang and Central Asia, and on to the east coast of the Mediterranean Sea.
Following Zhang Qian's embassy and report, commercial relations between China and Central as well as Western Asia flourished, as many Chinese missions were sent throughout the 1st century BC, initiating the development of the Silk Road:
:"The largest of these embassies to foreign states numbered several hundred persons, while even the smaller parties included over 100 members... In the course of one year anywhere from five to six to over ten parties would be sent out." .
China also sent missions to Parthia, which were followed up by reciprocal missions from Parthian envoys around 100 BC:
:"When the Han envoy first visited the kingdom of , the king of Anxi dispatched a party of 20,000 horsemen to meet them on the eastern border of the kingdom... When the Han envoys set out again to return to China, the king of Anxi dispatched envoys of his own to accompany them... The emperor was delighted at this." .
By AD 97 the Chinese general Ban Chao had embarked on a military expedition as far west as the landmass encompassed by present-day Ukraine in pursuit of fleeing Xiongnu insurgents, and returned eastward to establish base on the shores of the Caspian Sea with 70,000 men and established direct military contacts with the Parthian Empire, also dispatching an envoy to Rome in the person of Gan Ying.
Several Roman embassies to China are recounted in Chinese history, starting with a ''Hou Hanshu'' account of a convoy set out by emperor Antoninus Pius that reached the Chinese capital Luoyang in 166 and was greeted by . Good exchanges such as Chinese silk, African ivory, and Roman incense increased the contacts between the East and West.
Contacts with the Kushan Empire led to the introduction of Buddhism to China from India in the first century.
Rise of landholding class
To secure funding for his triumphant campaigns against the Xiongnu, Emperor Wu relinquished land control to merchants and the rich, and in effect legalized the privatization of lands. Land taxes were based on the sizes of fields instead of on income. The harvest could not always pay the taxes completely as incomes from selling harvest were often market-driven and a stable amount could not be guaranteed, especially not after harvest-reducing natural disasters. Merchants and prominent families then lured peasants to sell their lands since land accumulation guaranteed living standards of theirs and their descendants' in the agricultural society of China. Lands were hence accumulating into a new class of landholding families. The Han government in turn imposed more taxes on the remaining independent servants in order to make up the tax losses, therefore encouraging more peasants to come under the landholding elite or the landlords. This could be seen through such examples as the written evidence in the ''Yan Tie Lun'' , written about 80 BC, where the Lord Grand Secretary is quoted in this passage in his support of nationalizing the salt and iron industries:
Ideally the peasants pay the landlords certain periodic amount of income, who in turn provide protection against crimes and other hazards. In fact an increasing number of peasant population in the prosperous Han society and limited amount of lands provided the elite to elevate their standards for any new subordinate peasants. The inadequate education and often complete illiteracy of peasants forced them into a living of providing physical services, which were mostly farming in an agricultural society. The peasants, without other professions for their better living, compromised to the lowered standard and sold their harvest to pay their landlords. In fact they often had to delay the payment or borrow money from their landlords in the aftermath of natural disasters that reduced harvests. To make the situation worse, some Han rulers double-taxed the peasants. Eventually the living conditions of the peasants worsened as they solely depended on the harvest of the land they once owned.
The landholding elite and landlords, for their part, provided inaccurate information of subordinate peasants and lands to avoid paying taxes; to this very end corruption and incompetence of the Confucian scholar gentry on economics would play a vital part. Han court officials who attempted to strip lands out of the landlords faced such enormous resistance that their policies would never be put in to place. In fact only a member of the landholding families, for instance Wang Mang, was able to put his reforming ideals into effect despite failures of his "turning the clock back" policies.
The Han government kept records on people's property to assess taxes. Yet government officials and secretaries weren't the only ones documenting property. In the Han period the prototype of contractual language and privately signed contracts appear for those wishing to keep their own private documents on their property for later use in court if necessary. However, creating signed contracts with documented witnesses and scribes was not in common use until the , while contractual language did not "permeate Chinese life" until the Yuan Dynasty , according to historians Valerie Hansen and Timothy Brook.
Interruption of Han rule
After 200 years, Han rule was interrupted briefly during AD 9?24 by Wang Mang, a reformer and a member of the landholding families. The economic situation deteriorated at the end of Western Han Dynasty. Wang Mang, believing the Liu family had lost the Mandate of Heaven, took power and turned the clock back with vigorous monetary and land reforms, which damaged the economy even further.
Restoration and new golden age
A distant relative of Liu royalty, , prevailed after a number of agrarian rebellions had overthrown Wang Mang's Xin Dynasty, and he reestablished the Han Dynasty in AD 25. He and his son Emperor Ming of Han and grandson Emperor Zhang of Han were generally considered able emperors whose reigns were the prime of the Eastern Han Dynasty. Military speaking, a new golden age also reappeared. In 97, Ban Chao and his troops went as far to reach the Caspian Sea, while this familly also provide notorious generals and historians.
Decrease of administrative fairness and fall of Eastern Han Dynasty
After Emperor Zhang, however, the dynasty fell into states of corruption and political power struggles among three groups of powerful individuals --
eunuchs, empresses' clans, and Confucian scholar-officials. None of these three parties was able to improve the harsh livelihood of peasants under the landholding families. Land privatizations and accumulations on the hands of the elite affected the societies of the Three Kingdoms and the Southern and Northern Dynasties that the landholding elite held the actual driving and ruling power of the country. Successful ruling entities worked with these families, and consequently their policies favored the elite. Adverse effects of the Nine grade controller system or the Nine rank system were brilliant examples.
Taiping Taoist ideals of equal rights and equal land distribution quickly spread throughout the peasantry. As a result, the peasant insurgents of the Yellow Turban Rebellion swarmed the North China Plain, the main agricultural sector of the country. Power of the Liu royalty then fell into the hands of local governors and warlords, despite suppression of the main upraising of Zhang Jiao and his brothers. Three overlords eventually succeeded in control of the whole of China proper, ushering in the period of the Three Kingdoms. The figurehead reigned until 220 when Cao Pi forced his abdication.