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128-609: The city spans an area of 1,432.32 square kilometres (553.02 sq mi), and has a population of 560,234 as of 2019. The area was first incorporated under the Han dynasty as Qucheng County ( simplified Chinese : 曲成县 ; traditional Chinese : 曲成縣 ). Gold was discovered at Zhaoyuan in the Tang dynasty . The myth accompanying the city's discovery of gold is that a giant tortoise named Ao once told villagers struggling with famine to dig, and upon digging, they struck gold. The county

256-399: A fault . Water often lubricates faults, filling in fractures and jogs. About 10 kilometres (6.2 mi) below the surface, under very high temperatures and pressures, the water carries high concentrations of carbon dioxide, silica, and gold. During an earthquake, the fault jog suddenly opens wider. The water inside the void instantly vaporizes, flashing to steam and forcing silica, which forms

384-644: A limited engagement at Mayi involving the assassination of the Chanyu would throw the Xiongnu realm into chaos and benefit the Han. When this plot failed in 133 BC, Emperor Wu launched a series of massive military invasions into Xiongnu territory. The assault culminated in 119 BC at the Battle of Mobei , when Han commanders Huo Qubing ( d.  117 BC ) and Wei Qing ( d.  106 BC ) forced

512-595: A Greek sailor had visited. Emperor Zhang 's ( r.  75–88 AD ) reign came to be viewed by later Eastern Han scholars as the high point of the dynastic house. Subsequent reigns were increasingly marked by eunuch intervention in court politics and their involvement in the violent power struggles of the imperial consort clans . In 92 AD, with the aid of the eunuch Zheng Zhong ( d.  107 AD ), Emperor He ( r.  88–105 AD ) had Empress Dowager Dou ( d.  97 AD ) put under house arrest and her clan stripped of power. This

640-463: A change which debased the value of coinage. Although these reforms provoked considerable opposition, Wang's regime met its ultimate downfall with the massive floods of c.  3  AD and 11 AD. Gradual silt build-up in the Yellow River had raised its water level and overwhelmed the flood control works . The Yellow River split into two new branches: one emptying to the north and

768-448: A coalition of former officials and officers against Dong, who burned Luoyang to the ground and resettled the court at Chang'an in May 191 AD. Dong Zhuo later poisoned Emperor Shao. Dong was killed by his adopted son Lü Bu ( d.  198 AD ) in a plot hatched by Wang Yun ( d.  192 AD ). Emperor Xian fled from Chang'an in 195 AD to the ruins of Luoyang. Xian

896-416: A coup against the eunuchs Hou Lan ( d.  172 AD ), Cao Jie ( d.  181 AD ), and Wang Fu ( 王甫 ). When the plot was uncovered, the eunuchs arrested Empress Dowager Dou ( d.  172 AD ) and Chen Fan. General Zhang Huan ( 張奐 ) favoured the eunuchs. He and his troops confronted Dou Wu and his retainers at the palace gate where each side shouted accusations of treason against

1024-527: A descendant of Emperor Jing ( r.  157–141 BC ), attempted to restore the Han dynasty and occupied Chang'an as his capital. However, he was overwhelmed by the Red Eyebrow rebels who deposed, assassinated, and replaced him with the puppet monarch Liu Penzi . Gengshi's distant cousin Liu Xiu, known posthumously as Emperor Guangwu ( r.  25–57 AD ), after distinguishing himself at

1152-483: A dilute solution of gold(III) chloride or chlorauric acid . Unlike sulfur, phosphorus reacts directly with gold at elevated temperatures to produce gold phosphide (Au 2 P 3 ). Gold readily dissolves in mercury at room temperature to form an amalgam , and forms alloys with many other metals at higher temperatures. These alloys can be produced to modify the hardness and other metallurgical properties, to control melting point or to create exotic colors. Gold

1280-579: A gold-from-seawater swindle in the United States in the 1890s, as did an English fraudster in the early 1900s. Fritz Haber did research on the extraction of gold from sea water in an effort to help pay Germany 's reparations following World War I . Based on the published values of 2 to 64 ppb of gold in seawater, a commercially successful extraction seemed possible. After analysis of 4,000 water samples yielding an average of 0.004 ppb, it became clear that extraction would not be possible, and he ended

1408-830: A golden hue to metallic caesium . Common colored gold alloys include the distinctive eighteen-karat rose gold created by the addition of copper. Alloys containing palladium or nickel are also important in commercial jewelry as these produce white gold alloys. Fourteen-karat gold-copper alloy is nearly identical in color to certain bronze alloys, and both may be used to produce police and other badges . Fourteen- and eighteen-karat gold alloys with silver alone appear greenish-yellow and are referred to as green gold . Blue gold can be made by alloying with iron , and purple gold can be made by alloying with aluminium . Less commonly, addition of manganese , indium , and other elements can produce more unusual colors of gold for various applications. Colloidal gold , used by electron-microscopists,

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1536-567: A large alluvial deposit. The mines at Roşia Montană in Transylvania were also very large, and until very recently, still mined by opencast methods. They also exploited smaller deposits in Britain , such as placer and hard-rock deposits at Dolaucothi . The various methods they used are well described by Pliny the Elder in his encyclopedia Naturalis Historia written towards the end of

1664-462: A novel type of metal-halide perovskite material consisting of Au and Au cations in its crystal structure has been found. It has been shown to be unexpectedly stable at normal conditions. Gold pentafluoride , along with its derivative anion, AuF − 6 , and its difluorine complex , gold heptafluoride , is the sole example of gold(V), the highest verified oxidation state. Some gold compounds exhibit aurophilic bonding , which describes

1792-413: 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

1920-578: A request by Kushan ruler Vima Kadphises ( r.   c.  90  – c.  100 AD –  ) for a marriage alliance with the Han was rejected in AD ;90, he sent his forces to Wakhan (modern-day Afghanistan) to attack Ban Chao. The conflict ended with the Kushans withdrawing because of lack of supplies. In AD 91, the office of Protector General of the Western Regions

2048-428: A series of reforms that limited the power of these kingdoms in 145, dividing their former territories into new commanderies under central control. Kings were no longer able to appoint their own staff; this duty was assumed by the imperial court. Kings became nominal heads of their fiefs and collected a portion of tax revenues as their personal incomes. The kingdoms were never entirely abolished and existed throughout

2176-401: A sheet of 1 square metre (11 sq ft), and an avoirdupois ounce into 28 square metres (300 sq ft). Gold leaf can be beaten thin enough to become semi-transparent. The transmitted light appears greenish-blue because gold strongly reflects yellow and red. Such semi-transparent sheets also strongly reflect infrared light, making them useful as infrared (radiant heat) shields in

2304-470: A significant amount of gold deposits, largely concentrated in its northeast. Zhaojin Mining has its headquarters located in the city. Additionally, Linglong Tire is headquartered in the city. National Highway 206 runs through Zhaoyuan. A large golden statue of Ao , a Chinese mythical giant turtle is located in the village of Oujiakuang ( Chinese : 欧家夼村 ; pinyin : Ōujiākuǎng Cūn ), in

2432-520: A solution of Au(OH) 3 in concentrated H 2 SO 4 produces red crystals of gold(II) sulfate , Au 2 (SO 4 ) 2 . Originally thought to be a mixed-valence compound, it has been shown to contain Au 4+ 2 cations, analogous to the better-known mercury(I) ion, Hg 2+ 2 . A gold(II) complex, the tetraxenonogold(II) cation, which contains xenon as a ligand, occurs in [AuXe 4 ](Sb 2 F 11 ) 2 . In September 2023,

2560-399: A state pension and a territorial fiefdom . Holders of the rank immediately below, that of ordinary marquess, received a pension, but had no territorial rule. Scholar-bureaucrats who served in government belonged to the wider commoner social class and were ranked just below nobles in social prestige. The highest government officials could be enfeoffed as marquesses. Gold Gold

2688-545: A successful overthrow of her regime to enthrone Emperor Shun of Han ( r.  125–144 AD ). Yan was placed under house arrest, her relatives were either killed or exiled, and her eunuch allies were slaughtered. The regent Liang Ji ( d.  159 AD ), brother of Empress Liang Na ( d.  150 AD ), had the brother-in-law of Consort Deng Mengnü ( d.  165 AD ) killed after Deng Mengnü resisted Liang Ji's attempts to control her. Afterward, Emperor Huan employed eunuchs to depose Liang Ji, who

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2816-474: A war to determine who would have hegemony over China, which had fissured into Eighteen Kingdoms , each claiming allegiance to either Xiang Yu or Liu Bang. Although Xiang Yu proved to be an effective commander, Liu Bang defeated him at the Battle of Gaixia (202 BC) in modern-day Anhui . Liu Bang assumed the title of Emperor at the urging of his followers and is known posthumously as Emperor Gaozu ( r.  202–195 BC ). Chang'an (modern Xi'an)

2944-470: Is Au with a half-life of 2.27 days. Gold's least stable isomer is Au with a half-life of only 7 ns. Au has three decay paths: β decay, isomeric transition , and alpha decay. No other isomer or isotope of gold has three decay paths. The possible production of gold from a more common element, such as lead , has long been a subject of human inquiry, and the ancient and medieval discipline of alchemy often focused on it; however,

3072-696: Is Au , which decays by proton emission with a half-life of 30 μs. Most of gold's radioisotopes with atomic masses below 197 decay by some combination of proton emission , α decay , and β decay . The exceptions are Au , which decays by electron capture, and Au , which decays most often by electron capture (93%) with a minor β decay path (7%). All of gold's radioisotopes with atomic masses above 197 decay by β decay. At least 32 nuclear isomers have also been characterized, ranging in atomic mass from 170 to 200. Within that range, only Au , Au , Au , Au , and Au do not have isomers. Gold's most stable isomer

3200-689: Is 607.3 millimetres (23.91 in). Zhaoyuan administers five subdistricts and nine towns . Zhaoyuan's five subdistricts are Luofeng Subdistrict  [ zh ] , Quanshan Subdistrict , Mengzhi Subdistrict  [ zh ] , Wenquan Subdistrict  [ zh ] , and Daqinjia Subdistrict  [ zh ] . Zhaoyuan's nine towns are Xinzhuang  [ zh ] , Canzhuang  [ zh ] , Jinling  [ zh ] , Biguo  [ zh ] , Linglong  [ zh ] , Zhangxing  [ zh ] , Xiadian  [ zh ] , Fushan  [ zh ] , and Qishan  [ zh ] . The city has

3328-417: Is a chemical element with the chemical symbol Au (from Latin aurum ) and atomic number 79. In its pure form, it is a bright , slightly orange-yellow, dense, soft, malleable , and ductile metal . Chemically, gold is a transition metal , a group 11 element , and one of the noble metals . It is one of the least reactive chemical elements, being the second-lowest in the reactivity series . It

3456-648: Is also known, an example of a mixed-valence complex . Gold does not react with oxygen at any temperature and, up to 100 °C, is resistant to attack from ozone: Au + O 2 ⟶ ( no reaction ) {\displaystyle {\ce {Au + O2 ->}}({\text{no reaction}})} Au + O 3 → t < 100 ∘ C ( no reaction ) {\displaystyle {\ce {Au{}+O3->[{} \atop {t<100^{\circ }{\text{C}}}]}}({\text{no reaction}})} Some free halogens react to form

3584-520: Is also used in infrared shielding, the production of colored glass , gold leafing , and tooth restoration . Certain gold salts are still used as anti-inflammatory agents in medicine. Gold is the most malleable of all metals. It can be drawn into a wire of single-atom width, and then stretched considerably before it breaks. Such nanowires distort via the formation, reorientation, and migration of dislocations and crystal twins without noticeable hardening. A single gram of gold can be beaten into

3712-427: Is always richer at the exposed surface of gold-bearing veins, owing to the oxidation of accompanying minerals followed by weathering; and by washing of the dust into streams and rivers, where it collects and can be welded by water action to form nuggets. Gold sometimes occurs combined with tellurium as the minerals calaverite , krennerite , nagyagite , petzite and sylvanite (see telluride minerals ), and as

3840-517: Is attributed to wind-blown dust or rivers. At 10 parts per quadrillion, the Earth's oceans would hold 15,000 tonnes of gold. These figures are three orders of magnitude less than reported in the literature prior to 1988, indicating contamination problems with the earlier data. A number of people have claimed to be able to economically recover gold from sea water , but they were either mistaken or acted in an intentional deception. Prescott Jernegan ran

3968-470: Is found in ores in rock formed from the Precambrian time onward. It most often occurs as a native metal , typically in a metal solid solution with silver (i.e. as a gold/silver alloy ). Such alloys usually have a silver content of 8–10%. Electrum is elemental gold with more than 20% silver, and is commonly known as white gold . Electrum's color runs from golden-silvery to silvery, dependent upon

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4096-594: Is located in Zhaoyuan. Han dynasty This is an accepted version of this page 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

4224-472: Is most often called the oldest since this treasure is the largest and most diverse. Gold artifacts probably made their first appearance in Ancient Egypt at the very beginning of the pre-dynastic period, at the end of the fifth millennium BC and the start of the fourth, and smelting was developed during the course of the 4th millennium; gold artifacts appear in the archeology of Lower Mesopotamia during

4352-493: Is now northern Sichuan and southern Shaanxi , was not quelled until 215 AD. Zhang Jue's massive rebellion across eight provinces was annihilated by Han forces within a year; however, the following decades saw much smaller recurrent uprisings. Although the Yellow Turbans were defeated, many generals appointed during the crisis never disbanded their assembled militias and used these troops to amass power outside of

4480-542: Is now questioned. The gold-bearing Witwatersrand rocks were laid down between 700 and 950 million years before the Vredefort impact. These gold-bearing rocks had furthermore been covered by a thick layer of Ventersdorp lavas and the Transvaal Supergroup of rocks before the meteor struck, and thus the gold did not actually arrive in the asteroid/meteorite. What the Vredefort impact achieved, however,

4608-602: Is recorded in the Weilüe and Book of Later Han to have reached the court of Emperor Huan of Han ( r.  146–168 AD ) in AD 166, yet Rafe de Crespigny asserts that this was most likely a group of Roman merchants . In addition to Roman glasswares and coins found in China, Roman medallions from the reign of Antoninus Pius and his adopted son Marcus Aurelius have been found at Óc Eo in Vietnam. This

4736-427: Is red if the particles are small; larger particles of colloidal gold are blue. Gold has only one stable isotope , Au , which is also its only naturally occurring isotope, so gold is both a mononuclidic and monoisotopic element . Thirty-six radioisotopes have been synthesized, ranging in atomic mass from 169 to 205. The most stable of these is Au with a half-life of 186.1 days. The least stable

4864-553: Is resistant to most acids, though it does dissolve in aqua regia (a mixture of nitric acid and hydrochloric acid ), forming a soluble tetrachloroaurate anion . Gold is insoluble in nitric acid alone, which dissolves silver and base metals , a property long used to refine gold and confirm the presence of gold in metallic substances, giving rise to the term ' acid test '. Gold dissolves in alkaline solutions of cyanide , which are used in mining and electroplating . Gold also dissolves in mercury , forming amalgam alloys, and as

4992-484: Is similarly unaffected by most bases. It does not react with aqueous , solid , or molten sodium or potassium hydroxide . It does however, react with sodium or potassium cyanide under alkaline conditions when oxygen is present to form soluble complexes. Common oxidation states of gold include +1 (gold(I) or aurous compounds) and +3 (gold(III) or auric compounds). Gold ions in solution are readily reduced and precipitated as metal by adding any other metal as

5120-483: Is solid under standard conditions . Gold often occurs in free elemental ( native state ), as nuggets or grains, in rocks , veins , and alluvial deposits . It occurs in a solid solution series with the native element silver (as in electrum ), naturally alloyed with other metals like copper and palladium , and mineral inclusions such as within pyrite . Less commonly, it occurs in minerals as gold compounds, often with tellurium ( gold tellurides ). Gold

5248-589: Is the soluble form of gold encountered in mining. The binary gold halides , such as AuCl , form zigzag polymeric chains, again featuring linear coordination at Au. Most drugs based on gold are Au(I) derivatives. Au(III) (referred to as auric) is a common oxidation state, and is illustrated by gold(III) chloride , Au 2 Cl 6 . The gold atom centers in Au(III) complexes, like other d compounds, are typically square planar , with chemical bonds that have both covalent and ionic character. Gold(I,III) chloride

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5376-657: Is thought to have been delivered to Earth by asteroid impacts during the Late Heavy Bombardment , about 4 billion years ago. Gold which is reachable by humans has, in one case, been associated with a particular asteroid impact. The asteroid that formed Vredefort impact structure 2.020 billion years ago is often credited with seeding the Witwatersrand basin in South Africa with the richest gold deposits on earth. However, this scenario

5504-511: Is thought to have been produced in supernova nucleosynthesis , and from the collision of neutron stars , and to have been present in the dust from which the Solar System formed. Traditionally, gold in the universe is thought to have formed by the r-process (rapid neutron capture) in supernova nucleosynthesis , but more recently it has been suggested that gold and other elements heavier than iron may also be produced in quantity by

5632-416: Is unaffected by most acids. It does not react with hydrofluoric , hydrochloric , hydrobromic , hydriodic , sulfuric , or nitric acid . It does react with selenic acid , and is dissolved by aqua regia , a 1:3 mixture of nitric acid and hydrochloric acid . Nitric acid oxidizes the metal to +3 ions, but only in minute amounts, typically undetectable in the pure acid because of the chemical equilibrium of

5760-538: The Battle of Kunyang in 23 AD, was urged to succeed Gengshi as emperor. Under Guangwu's rule, the Han Empire was restored. Guangwu made Luoyang his capital in 25 AD, and by 27 his officers Deng Yu and Feng Yi had forced the Red Eyebrows to surrender and executed their leaders for treason . From 26 until 36 AD, Emperor Guangwu had to wage war against other regional warlords who claimed

5888-524: The Battle of Zhizhi , in modern Taraz , Kazakhstan. In 121 BC, Han forces expelled the Xiongnu from a vast territory spanning the Hexi Corridor to Lop Nur . They repelled a joint Xiongnu- Qiang invasion of this northwestern territory in 111 BC. In that same year, the Han court established four new frontier commanderies in this region to consolidate their control: Jiuquan , Zhangyi , Dunhuang , and Wuwei . The majority of people on

6016-743: The Buyeo Kingdom in Manchuria to the Ili River of the Wusun people. The Xianbei reached their apogee under Tanshihuai ( d.  AD 181 ), who consistently defeated Chinese armies. However, Tanshihuai's confederation disintegrated after his death. Ban Chao ( d.  AD 102 ) enlisted the aid of the Kushan Empire , which controlled territory across South and Central Asia, to subdue Kashgar and its ally Sogdiana. When

6144-666: The Chu (state) circulated the Ying Yuan , one kind of square gold coin. In Roman metallurgy , new methods for extracting gold on a large scale were developed by introducing hydraulic mining methods, especially in Hispania from 25 BC onwards and in Dacia from 106 AD onwards. One of their largest mines was at Las Medulas in León , where seven long aqueducts enabled them to sluice most of

6272-756: The Chu–Han Contention , the resulting Han dynasty was named after the Hanzhong fief. China's first imperial dynasty was the Qin dynasty (221–207 BC). The Qin united the Chinese Warring States by conquest, but their regime became unstable after the death of the first emperor Qin Shi Huang . Within four years, the dynasty's authority had collapsed in a rebellion. Two former rebel leaders, Xiang Yu ( d.  202 BC ) of Chu and Liu Bang ( d.  195 BC ) of Han , engaged in

6400-763: The Greco-Bactrian Kingdom ); he also gathered information on Shendu (the Indus River valley) and Anxi (the Parthian Empire ). All of these countries eventually received Han embassies. These connections marked the beginning of the Silk Road trade network that extended to the Roman Empire , bringing goods like Chinese silk and Roman glasswares between the two. From c.  115 BC until c.  60 BC , Han forces fought

6528-602: The Old Testament , starting with Genesis 2:11 (at Havilah ), the story of the golden calf , and many parts of the temple including the Menorah and the golden altar. In the New Testament , it is included with the gifts of the magi in the first chapters of Matthew. The Book of Revelation 21:21 describes the city of New Jerusalem as having streets "made of pure gold, clear as crystal". Exploitation of gold in

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6656-658: The Varna Necropolis near Lake Varna and the Black Sea coast, thought to be the earliest "well-dated" finding of gold artifacts in history. Several prehistoric Bulgarian finds are considered no less old – the golden treasures of Hotnitsa, Durankulak , artifacts from the Kurgan settlement of Yunatsite near Pazardzhik , the golden treasure Sakar, as well as beads and gold jewelry found in the Kurgan settlement of Provadia – Solnitsata ("salt pit"). However, Varna gold

6784-467: The Xiongnu , a nomadic confederation centred in the eastern Eurasian steppe . The Xiongnu defeated the Han in 200 BC , prompting the Han to appease the Xiongnu with a policy of marriage alliance and payments of tribute, though the Xiongnu continued to raid the Han's northern borders. Han policy changed in 133 BC, under Emperor Wu , when Han forces began a series of military campaigns to quell

6912-584: The Xiongnu , who were estranged from Han until their leader Bi ( 比 ), a rival claimant to the throne against his cousin Punu ( 蒲奴 ), submitted to Han as a tributary vassal in AD 50. This created two rival Xiongnu states: the Southern Xiongnu led by Bi, an ally of Han, and the Northern Xiongnu led by Punu, an enemy of Han. During the turbulent reign of Wang Mang, China lost control over

7040-575: The Yellow Turban Rebellion and Five Pecks of Rice Rebellion in 184 AD, largely because the court did not want to continue to alienate a significant portion of the gentry class who might otherwise join the rebellions. The Yellow Turbans and Five-Pecks-of-Rice adherents belonged to two different hierarchical Taoist religious societies led by faith healers Zhang Jue ( d.  184 AD ) and Zhang Lu ( d.  216 AD ), respectively. Zhang Lu's rebellion, in what

7168-470: The reducing agent . The added metal is oxidized and dissolves, allowing the gold to be displaced from solution and be recovered as a solid precipitate. Less common oxidation states of gold include −1, +2, and +5. The −1 oxidation state occurs in aurides, compounds containing the Au anion . Caesium auride (CsAu), for example, crystallizes in the caesium chloride motif; rubidium, potassium, and tetramethylammonium aurides are also known. Gold has

7296-513: 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 oversaw periods of economic prosperity as well as significant growth in the money economy that had first been established during the Zhou dynasty ( c.  1050  – 256 BC). The coinage minted by

7424-499: The Eastern period. There were significant advances in science and technology during the Han period, including the emergence of papermaking , rudders for steering ships, negative numbers in mathematics , raised-relief maps , hydraulic -powered armillary spheres for astronomy , and seismometers that discerned the cardinal direction of distant earthquakes by use of inverted pendulums . The Han dynasty had many conflicts with

7552-452: The Han as equal partners in a royal marriage alliance, but the Han were forced to send large amounts of tribute items such as silk clothes, food, and wine to the Xiongnu. Despite the tribute and negotiation between Laoshang Chanyu ( r.  174–160 BC ) and Emperor Wen ( r.  180–157 BC ) to reopen border markets, many of the Chanyu 's subordinates chose not to obey

7680-726: The Imperial University on a dubious charge of treason. In 167 AD, the Grand Commandant Dou Wu ( d.  168 AD ) convinced his son-in-law, Emperor Huan, to release them. However, the emperor permanently barred Li Ying and his associates from serving in office, marking the beginning of the Partisan Prohibitions . Following Huan's death, Dou Wu and the Grand Tutor Chen Fan ( d.  168 AD ) attempted

7808-693: The Tarim Basin, which was conquered by the Northern Xiongnu in AD 63 and used as a base to invade the Hexi Corridor in Gansu . Dou Gu ( d.  88 AD ) defeated the Northern Xiongnu at the Battle of Yiwulu in AD 73, evicting them from Turpan and chasing them as far as Lake Barkol before establishing a garrison at Hami. After the new Protector General of the Western Regions Chen Mu ( d.  AD 75 )

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7936-514: The Xiongnu court to flee north of the Gobi Desert , and Han forces reached as far north as Lake Baikal . After Wu's reign, Han forces continued to fight the Xiongnu. The Xiongnu leader Huhanye ( r.  58–31 BC ) finally submitted to the Han as a tributary vassal in 51 BC. Huhanye's rival claimant to the throne, Zhizhi Chanyu ( r.  56–36 BC ), was killed by Han forces under Chen Tang and Gan Yanshou ( 甘延壽 ) at

8064-482: The Xiongnu over control of the oasis city-states in the Tarim Basin. The Han was eventually victorious and established the Protectorate of the Western Regions in 60 BC, which dealt with the region's defence and foreign affairs. The Han also expanded southward . The naval conquest of Nanyue in 111 BC expanded the Han realm into what are now modern Guangdong , Guangxi , and northern Vietnam. Yunnan

8192-487: The Xiongnu. The Xiongnu were eventually defeated and forced to accept a status as Han vassals , and the Xiongnu confederation fragmented. The Han conquered the Hexi Corridor and Inner Asian territory of the Tarim Basin from the Xiongnu, helping to establish the Silk Road . The lands north of the Han's borders were later overrun by the nomadic Xianbei confederation. Emperor Wu also launched successful conquests in

8320-546: The Yuan brothers, Zhang committed suicide by jumping into the Yellow River. General Dong Zhuo ( d.  192 AD ) found the young emperor and his brother wandering in the countryside. He escorted them safely back to the capital and was made Minister of Works , taking control of Luoyang and forcing Yuan Shao to flee. After Dong Zhuo demoted Emperor Shao and promoted his brother Liu Xie as Emperor Xian, Yuan Shao led

8448-429: The attackers were executed, and the other three received jail sentences ranging from seven years to life. Zhaoyuan's city center is located approximately 90 kilometres (56 mi) southwest of Yantai's urban center. The city's terrain is higher in the northeast, middle and west, and lower in the northwest and southeast The city's annual average temperature is 11 °C (52 °F), and its annual average precipitation

8576-528: The capital was moved eastward to Luoyang. The era from his reign until the fall of Han is known as the Eastern Han or Later Han (25–220 AD). The Eastern Han ( traditional Chinese : 東漢 ; simplified Chinese : 东汉 ; pinyin : Dōnghàn ), also known as the Later Han ( 後漢 ; 后汉 ; Hòuhàn ), formally began on 5 August AD 25, when Liu Xiu became Emperor Guangwu of Han . During

8704-412: The central government in 119 BC remained the standard in China until the Tang dynasty (618–907 AD). The period saw a number of limited institutional innovations. To finance its military campaigns and the settlement of newly conquered frontier territories, the Han government nationalised private salt and iron industries in 117 BC, creating government monopolies that were later repealed during

8832-445: The city's last township to be upgraded to a town. In late May 2014, five members of The Church of Almighty God , an outlawed new-age cult, entered a McDonald's in Zhaoyuan and began soliciting customers' phone numbers. When 37 year-old Wu Shuoyan refused to give her phone number to the group, they claimed she was an "evil spirit", and began beating her with chairs and a metal mop handle, ultimately killing her. In February 2015, two of

8960-434: The collapsing imperial authority. General-in-chief He Jin ( d.  189 AD ), half-brother to Empress He ( d.  189 AD ), plotted with Yuan Shao ( d.  202 AD ) to overthrow the eunuchs by having several generals march to the outskirts of the capital. There, in a written petition to Empress He, they demanded the eunuchs' execution. After a period of hesitation, Empress He consented. When

9088-1409: The corresponding gold halides. Gold is strongly attacked by fluorine at dull-red heat to form gold(III) fluoride AuF 3 . Powdered gold reacts with chlorine at 180 °C to form gold(III) chloride AuCl 3 . Gold reacts with bromine at 140 °C to form a combination of gold(III) bromide AuBr 3 and gold(I) bromide AuBr, but reacts very slowly with iodine to form gold(I) iodide AuI: 2 Au + 3 F 2 → Δ 2 AuF 3 {\displaystyle {\ce {2Au{}+3F2->[{} \atop \Delta ]2AuF3}}} 2 Au + 3 Cl 2 → Δ 2 AuCl 3 {\displaystyle {\ce {2Au{}+3Cl2->[{} \atop \Delta ]2AuCl3}}} 2 Au + 2 Br 2 → Δ AuBr 3 + AuBr {\displaystyle {\ce {2Au{}+2Br2->[{} \atop \Delta ]AuBr3{}+AuBr}}} 2 Au + I 2 → Δ 2 AuI {\displaystyle {\ce {2Au{}+I2->[{} \atop \Delta ]2AuI}}} Gold does not react with sulfur directly, but gold(III) sulfide can be made by passing hydrogen sulfide through

9216-424: The densest element, osmium , is 22.588 ± 0.015 g/cm . Whereas most metals are gray or silvery white, gold is slightly reddish-yellow. This color is determined by the frequency of plasma oscillations among the metal's valence electrons, in the ultraviolet range for most metals but in the visible range for gold due to relativistic effects affecting the orbitals around gold atoms. Similar effects impart

9344-689: The early 4th millennium. As of 1990, gold artifacts found at the Wadi Qana cave cemetery of the 4th millennium BC in West Bank were the earliest from the Levant. Gold artifacts such as the golden hats and the Nebra disk appeared in Central Europe from the 2nd millennium BC Bronze Age . The oldest known map of a gold mine was drawn in the 19th Dynasty of Ancient Egypt (1320–1200 BC), whereas

9472-490: The emperor was often a minor, ruled over by a regent such as the empress dowager or one of her male relatives. Ranked immediately below the emperor were the kings who were of the same Liu family clan. The rest of society, including nobles lower than kings and all commoners excluding slaves, belonged to one of twenty ranks ( ershi gongcheng 二十公乘 ). Each successive rank gave its holder greater pensions and legal privileges. The highest rank, of full marquess , came with

9600-593: The empire . The Han dynasty came to an end in 220 AD when Cao Pi , king of Wei , usurped the throne from Emperor Xian . According to the Records of the Grand Historian , after the collapse of the Qin dynasty the hegemon Xiang Yu appointed Liu Bang as prince of the small fief of Hanzhong , named after its location on the Han River (in modern southwest Shaanxi ). Following Liu Bang's victory in

9728-489: The empresses and empresses dowager . Imperial authority was also seriously challenged by large Taoist religious societies which instigated the Yellow Turban Rebellion and the Five Pecks of Rice Rebellion . Following the death of Emperor Ling ( r.  168–189 AD ), the palace eunuchs were massacred by military officers, allowing members of the aristocracy and military governors to become warlords and divide

9856-640: The eunuchs discovered this, however, they had her brother He Miao ( 何苗 ) rescind the order. The eunuchs assassinated He Jin on 22 September 189. Yuan Shao then besieged Luoyang's Northern Palace while his brother Yuan Shu ( d.  199 AD ) besieged the Southern Palace. On September 25 both palaces were breached and approximately two thousand eunuchs were killed. Zhang Rang had previously fled with Emperor Shao ( r.  189 AD ) and his brother Liu Xie—the future Emperor Xian of Han ( r.  189–220 AD ). While being pursued by

9984-427: The family inheritance. His brothers Yuan Shang and Yuan Xi were killed in 207 AD by Gongsun Kang ( d.  221 AD ), who sent their heads to Cao Cao. After Cao's defeat at the naval Battle of Red Cliffs in 208 AD, China was divided into three spheres of influence, with Cao Cao dominating the north, Sun Quan (182–252 AD) dominating the south, and Liu Bei (161–223 AD) dominating

10112-591: The first written reference to gold was recorded in the 12th Dynasty around 1900 BC. Egyptian hieroglyphs from as early as 2600 BC describe gold, which King Tushratta of the Mitanni claimed was "more plentiful than dirt" in Egypt. Egypt and especially Nubia had the resources to make them major gold-producing areas for much of history. One of the earliest known maps, known as the Turin Papyrus Map , shows

10240-601: The frontier were soldiers. On occasion, the court forcibly moved peasant farmers to new frontier settlements, along with government-owned slaves and convicts who performed hard labour. The court also encouraged commoners, such as farmers, merchants, landowners, and hired labourers, to voluntarily migrate to the frontier. Even before the Han's expansion into Central Asia, diplomat Zhang Qian 's travels from 139 to 125 BC had established Chinese contacts with many surrounding civilizations. Zhang encountered Dayuan ( Fergana ), Kangju ( Sogdiana ), and Daxia ( Bactria , formerly

10368-403: The gold acts simply as a solute, this is not a chemical reaction . A relatively rare element, gold is a precious metal that has been used for coinage , jewelry , and other works of art throughout recorded history . In the past, a gold standard was often implemented as a monetary policy . Gold coins ceased to be minted as a circulating currency in the 1930s, and the world gold standard

10496-563: The highest electron affinity of any metal, at 222.8 kJ/mol, making Au a stable species, analogous to the halides . Gold also has a –1 oxidation state in covalent complexes with the group 4 transition metals, such as in titanium tetraauride and the analogous zirconium and hafnium compounds. These chemicals are expected to form gold-bridged dimers in a manner similar to titanium(IV) hydride . Gold(II) compounds are usually diamagnetic with Au–Au bonds such as [ Au(CH 2 ) 2 P(C 6 H 5 ) 2 ] 2 Cl 2 . The evaporation of

10624-547: The mineral quartz, and gold out of the fluids and onto nearby surfaces. The world's oceans contain gold. Measured concentrations of gold in the Atlantic and Northeast Pacific are 50–150 femtomol /L or 10–30 parts per quadrillion (about 10–30 g/km ). In general, gold concentrations for south Atlantic and central Pacific samples are the same (~50 femtomol/L) but less certain. Mediterranean deep waters contain slightly higher concentrations of gold (100–150 femtomol/L), which

10752-564: 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,

10880-459: The nobility, Wang Mang claimed on 10 January that the divine Mandate of Heaven called for the end of the Han dynasty and the beginning of his own: the Xin dynasty (9–23 AD). Wang Mang initiated a series of major reforms that were ultimately unsuccessful. These reforms included outlawing slavery, nationalizing and equally distributing land between households, and introducing new currencies,

11008-411: The noble metals, it still forms many diverse compounds. The oxidation state of gold in its compounds ranges from −1 to +5, but Au(I) and Au(III) dominate its chemistry. Au(I), referred to as the aurous ion, is the most common oxidation state with soft ligands such as thioethers , thiolates , and organophosphines . Au(I) compounds are typically linear. A good example is Au(CN) − 2 , which

11136-687: The other to the south of the Shandong Peninsula , though Han engineers managed to dam the southern branch by 70 AD. The flood dislodged thousands of peasant farmers, many of whom joined roving bandit and rebel groups such as the Red Eyebrows to survive. Wang Mang's armies were incapable of quelling these enlarged rebel groups. Eventually, an insurgent mob forced their way into the Weiyang Palace and killed Wang Mang. The Gengshi Emperor ( r.  23–25 AD ),

11264-560: The other. When the retainers gradually deserted Dou Wu, he was forced to commit suicide. Under Emperor Ling ( r.  168–189 AD ) the eunuchs had the partisan prohibitions renewed and expanded, while also auctioning off top government offices. Many affairs of state were entrusted to the eunuchs Zhao Zhong ( d.  189 AD ) and Zhang Rang ( d.  189 AD ) while Emperor Ling spent much of his time roleplaying with concubines and participating in military parades. The Partisan Prohibitions were repealed during

11392-576: The plan of a gold mine in Nubia together with indications of the local geology . The primitive working methods are described by both Strabo and Diodorus Siculus , and included fire-setting . Large mines were also present across the Red Sea in what is now Saudi Arabia . Gold is mentioned in the Amarna letters numbered 19 and 26 from around the 14th century BC. Gold is mentioned frequently in

11520-464: The project. The earliest recorded metal employed by humans appears to be gold, which can be found free or " native ". Small amounts of natural gold have been found in Spanish caves used during the late Paleolithic period, c.  40,000 BC . The oldest gold artifacts in the world are from Bulgaria and are dating back to the 5th millennium BC (4,600 BC to 4,200 BC), such as those found in

11648-690: The r-process in the collision of neutron stars . In both cases, satellite spectrometers at first only indirectly detected the resulting gold. However, in August 2017, the spectroscopic signatures of heavy elements, including gold, were observed by electromagnetic observatories in the GW170817 neutron star merger event, after gravitational wave detectors confirmed the event as a neutron star merger. Current astrophysical models suggest that this single neutron star merger event generated between 3 and 13 Earth masses of gold. This amount, along with estimations of

11776-620: The rare bismuthide maldonite ( Au 2 Bi ) and antimonide aurostibite ( AuSb 2 ). Gold also occurs in rare alloys with copper , lead , and mercury : the minerals auricupride ( Cu 3 Au ), novodneprite ( AuPb 3 ) and weishanite ( (Au,Ag) 3 Hg 2 ). A 2004 research paper suggests that microbes can sometimes play an important role in forming gold deposits, transporting and precipitating gold to form grains and nuggets that collect in alluvial deposits. A 2013 study has claimed water in faults vaporizes during an earthquake, depositing gold. When an earthquake strikes, it moves along

11904-420: The rate of occurrence of these neutron star merger events, suggests that such mergers may produce enough gold to account for most of the abundance of this element in the universe. Because the Earth was molten when it was formed , almost all of the gold present in the early Earth probably sank into the planetary core . Therefore, as hypothesized in one model, most of the gold in the Earth's crust and mantle

12032-935: The reaction. However, the ions are removed from the equilibrium by hydrochloric acid, forming AuCl − 4 ions, or chloroauric acid , thereby enabling further oxidation: 2 Au + 6 H 2 SeO 4 → 200 ∘ C Au 2 ( SeO 4 ) 3 + 3 H 2 SeO 3 + 3 H 2 O {\displaystyle {\ce {2Au{}+6H2SeO4->[{} \atop {200^{\circ }{\text{C}}}]Au2(SeO4)3{}+3H2SeO3{}+3H2O}}} Au + 4 HCl + HNO 3 ⟶ HAuCl 4 + NO ↑ + 2 H 2 O {\displaystyle {\ce {Au{}+4HCl{}+HNO3->HAuCl4{}+NO\uparrow +2H2O}}} Gold

12160-603: The remainder of Western and Eastern Han. To the north of China proper , the nomadic Xiongnu chieftain Modu Chanyu ( r.  209–174 BC ) conquered various tribes inhabiting the eastern portion of the Eurasian Steppe . By the end of his reign, he controlled the Inner Asian regions of Manchuria , Mongolia , and the Tarim Basin , subjugating over twenty states east of Samarkand . Emperor Gaozu

12288-473: The rest of the gold on Earth is thought to have been incorporated into the planet since its very beginning, as planetesimals formed the mantle . In 2017, an international group of scientists established that gold "came to the Earth's surface from the deepest regions of our planet", the mantle, as evidenced by their findings at Deseado Massif in the Argentinian Patagonia . On Earth, gold

12416-616: The salt and iron monopolies were eventually abolished in the early Eastern Han. The issuing of coinage remained a central government monopoly throughout the rest of the Han dynasty. The government monopolies were eventually repealed when a political faction known as the Reformists gained greater influence in the court. The Reformists opposed the Modernist faction that had dominated court politics in Emperor Wu's reign and during

12544-486: The same result and showing that the isotopes of gold produced by it were all radioactive . In 1980, Glenn Seaborg transmuted several thousand atoms of bismuth into gold at the Lawrence Berkeley Laboratory. Gold can be manufactured in a nuclear reactor, but doing so is highly impractical and would cost far more than the value of the gold that is produced. Although gold is the most noble of

12672-486: The silver content. The more silver, the lower the specific gravity . Native gold occurs as very small to microscopic particles embedded in rock, often together with quartz or sulfide minerals such as " fool's gold ", which is a pyrite . These are called lode deposits. The metal in a native state is also found in the form of free flakes, grains or larger nuggets that have been eroded from rocks and end up in alluvial deposits called placer deposits . Such free gold

12800-479: The south , annexing Nanyue in 111 BC and Dian in 109 BC . He further expanded Han territory into the northern Korean Peninsula , where Han forces conquered Gojoseon and established the Xuantu and Lelang commanderies in 108 BC. After 92 AD, palace eunuchs increasingly involved themselves in the dynasty's court politics, engaging in violent power struggles between various consort clans of

12928-450: The south-east corner of the Black Sea is said to date from the time of Midas , and this gold was important in the establishment of what is probably the world's earliest coinage in Lydia around 610 BC. The legend of the golden fleece dating from eighth century BCE may refer to the use of fleeces to trap gold dust from placer deposits in the ancient world. From the 6th or 5th century BC,

13056-479: The subsequent regency of Huo Guang ( d.  68 BC ). The Modernists argued for an aggressive and expansionary foreign policy supported by revenues from heavy government intervention in the private economy. The Reformists, however, overturned these policies, favouring a cautious, non-expansionary approach to foreign policy, frugal budget reform, and lower tax-rates imposed on private entrepreneurs. Wang Zhengjun (71 BC – 13 AD)

13184-436: The tendency of gold ions to interact at distances that are too long to be a conventional Au–Au bond but shorter than van der Waals bonding . The interaction is estimated to be comparable in strength to that of a hydrogen bond . Well-defined cluster compounds are numerous. In some cases, gold has a fractional oxidation state. A representative example is the octahedral species {Au( P(C 6 H 5 ) 3 )} 2+ 6 . Gold

13312-461: The title of emperor; when these warlords were defeated, China reunified under the Han. The period between the foundation of the Han dynasty and Wang Mang's reign is known as the Western Han ( 西漢 ; 西汉 ; Xīhàn ) or Former Han ( 前漢 ; 前汉 ; Qiánhàn ) (206 BC – 9 AD). During this period the capital was at Chang'an (modern Xi'an ). From the reign of Guangwu

13440-531: The town of Linglong  [ zh ] . Located in Luoshan National Forest Park ( simplified Chinese : 罗山国家森林公园 ; traditional Chinese : 羅山國家森林公園 ), the statue is Asia's largest statue of Ao , and is located at 37°27′36″N 120°28′22″E  /  37.46000°N 120.47278°E  / 37.46000; 120.47278 . The statue is 15 meters tall and 20 meters long. The Qucheng Ancient City Site  [ zh ]

13568-403: The transmutation of the chemical elements did not become possible until the understanding of nuclear physics in the 20th century. The first synthesis of gold was conducted by Japanese physicist Hantaro Nagaoka , who synthesized gold from mercury in 1924 by neutron bombardment. An American team, working without knowledge of Nagaoka's prior study, conducted the same experiment in 1941, achieving

13696-472: The treaty and periodically raided Han territories south of the Great Wall for additional goods. In a court conference assembled by Emperor Wu ( r.  141–87 BC ) in 135 BC, the majority consensus of the ministers was to retain the heqin agreement. Emperor Wu accepted this, despite continuing Xiongnu raids. However, a court conference the following year convinced the majority that

13824-417: The visors of heat-resistant suits and in sun visors for spacesuits . Gold is a good conductor of heat and electricity . Gold has a density of 19.3 g/cm , almost identical to that of tungsten at 19.25 g/cm ; as such, tungsten has been used in the counterfeiting of gold bars , such as by plating a tungsten bar with gold. By comparison, the density of lead is 11.34 g/cm , and that of

13952-400: The war with Chu, Emperor Gaozu enfeoffed some of them as kings. By 196, the Han court had replaced all of these kings with royal Liu family members, with the lone exception of Changsha . The loyalty of non-relatives to the emperor was questioned, and after several insurrections by Han kings—with the largest being the Rebellion of the Seven States in 154—the imperial court began enacting

14080-550: The west. Cao Cao died in March 220 AD. By December his son Cao Pi (187–226 AD) had Emperor Xian relinquish the throne to him and is known posthumously as Emperor Wen of Wei . This formally ended the Han dynasty and initiated an age of conflict between the Three Kingdoms : Cao Wei , Eastern Wu , and Shu Han . In the hierarchical social order, the emperor was at the apex of Han society and government. However,

14208-411: The widespread rebellion against Wang Mang , the state of Goguryeo was free to raid Han's Korean commanderies ; Han did not reaffirm its control over the region until AD 30. The Trưng Sisters of Vietnam rebelled against Han in AD 40. Their rebellion was crushed by Han general Ma Yuan ( d.  AD 49 ) in a campaign from AD 42 to 43. Wang Mang renewed hostilities against

14336-787: Was abandoned for a fiat currency system after the Nixon shock measures of 1971. In 2020, the world's largest gold producer was China, followed by Russia and Australia. As of 2020 , a total of around 201,296 tonnes of gold exist above ground. This is equal to a cube, with each side measuring roughly 21.7 meters (71 ft). The world's consumption of new gold produced is about 50% in jewelry, 40% in investments , and 10% in industry . Gold's high malleability, ductility, resistance to corrosion and most other chemical reactions, as well as conductivity of electricity have led to its continued use in corrosion-resistant electrical connectors in all types of computerized devices (its chief industrial use). Gold

14464-438: Was appointed regent as Marshall of State on 16 August under Emperor Ping ( r.   1 BC – 6 AD). When Ping died on 3 February 6 AD, Ruzi Ying ( d.  25 AD ) was chosen as the heir and Wang Mang was appointed to serve as acting emperor for the child. Wang promised to relinquish his control to Liu Ying once he came of age. Despite this promise, and against protest and revolts from

14592-903: Was brought into the Han realm with the conquest of the Dian Kingdom in 109 BC, followed by parts of the Korean Peninsula with the Han conquest of Gojoseon and establishment of the Xuantu and Lelang commanderies in 108 BC. The first nationwide census in Chinese history was taken in 2 AD; the Han's total population was registered as comprising 57,671,400 individuals across 12,366,470 households. To pay for his military campaigns and colonial expansion, Emperor Wu nationalised several private industries. He created central government monopolies administered largely by former merchants . These monopolies included salt, iron, and liquor production, as well as bronze coinage . The liquor monopoly lasted only from 98 to 81 BC, and

14720-611: Was chosen as the new capital of the reunified empire under Han. At the beginning of the Western Han ( traditional Chinese : 西漢 ; simplified Chinese : 西汉 ; pinyin : Xīhàn ), also known as the Former Han ( 前漢 ; 前汉 ; Qiánhàn ), thirteen centrally-controlled commanderies —including the capital region—existed in the western third of the empire, while the eastern two-thirds were divided into ten semi-autonomous kingdoms . To placate his prominent commanders from

14848-490: Was convinced by the accusations of the eunuchs Li Run ( 李閏 ) and Jiang Jing ( 江京 ) that Deng and her family had planned to depose him. An dismissed Deng's clan members from office, exiled them, and forced many to commit suicide. After An's death, his wife, Empress Dowager Yan ( d.  126 AD ) placed the child Marquess of Beixiang on the throne in an attempt to retain power within her family. However, palace eunuch Sun Cheng ( d.  132 AD ) masterminded

14976-460: Was divided into three subdistricts : Luofeng Subdistrict  [ zh ] , Quanshan Subdistrict , and Mengzhi Subdistrict  [ zh ] . The Fifth National Population Census of the People's Republic of China reported that Zhaoyuan had a population of 593,705. On December 19, 2000, Dahuchenjia Township ( simplified Chinese : 大户陈家乡 ; traditional Chinese : 大戶陳家鄉 ) became

15104-487: Was first empress, then empress dowager , and finally grand empress dowager during the reigns of the Emperors Yuan ( r.  49–33 BC ), Cheng ( r.  33–7 BC ), and Ai ( r.  7–1 BC ), respectively. During this time, a succession of her male relatives held the title of regent. Following the death of Ai, Wang Zhengjun's nephew Wang Mang (45 BC – 23 AD)

15232-446: Was in revenge for Dou's purging of the clan of his natural mother— Consort Liang —and then concealing her identity from him. After Emperor He's death, his wife Empress Deng Sui ( d.  121 AD ) managed state affairs as the regent empress dowager during a turbulent financial crisis and widespread Qiang rebellion that lasted from 107 to 118 AD. When Empress Dowager Deng died, Emperor An ( r.  106–125 AD )

15360-650: Was killed by allies of the Xiongnu in Karasahr and Kucha , the garrison at Hami was withdrawn. At the Battle of Ikh Bayan in AD 89, Dou Xian ( d.  AD 92 ) defeated the Northern Xiongnu chanyu who then retreated into the Altai Mountains . After the Northern Xiongnu fled into the Ili River valley in AD 91, the nomadic Xianbei occupied the area from the borders of

15488-454: Was named Zhaoyuan County ( simplified Chinese : 招远县 ; traditional Chinese : 招遠縣 ) in 1131. Five townships in Zhaoyuan were upgraded to towns on September 1, 1988. On December 21, 1991, Zhaoyuan was upgraded from a county to a county-level city . Throughout the mid-1990s, three more townships were upgraded to towns. On January 11, 1999, the town of Zhaocheng ( simplified Chinese : 招城镇 ; traditional Chinese : 招城鎮 )

15616-664: Was near the commandery of Rinan where Chinese sources claim the Romans first landed, as well as embassies from Tianzhu in northern India in 159 and 161. Óc Eo is also thought to be the port city " Cattigara " described by Ptolemy in his Geography ( c.  150 AD ) as lying east of the Golden Chersonese ( Malay Peninsula ) along the Magnus Sinus (i.e. the Gulf of Thailand and South China Sea ), where

15744-450: Was persuaded by Cao Cao (155–220 AD), then Governor of Yan Province in modern western Shandong and eastern Henan , to move the capital to Xuchang in 196 AD. Yuan Shao challenged Cao Cao for control over the emperor. Yuan's power was greatly diminished after Cao defeated him at the Battle of Guandu in 200 AD. After Yuan died, Cao killed Yuan Shao's son Yuan Tan (173–205 AD), who had fought with his brothers over

15872-595: Was reinstated when it was bestowed on Ban Chao. Foreign travellers to the Eastern Han empire included Buddhist monks who translated works into Chinese , such as An Shigao from Parthia, and Lokaksema from Kushan-era Gandhara . In addition to tributary relations with the Kushans, the Han empire received gifts from sovereigns in the Parthian Empire , as well as from kings in modern Burma and Japan . He also initiated an unsuccessful mission to Rome in AD 97 with Gan Ying as emissary. A Roman embassy of Emperor Marcus Aurelius ( r.  161–180 AD )

16000-483: 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

16128-413: Was then forced to commit suicide. Students from the imperial university organized a widespread student protest against the eunuchs of Emperor Huan's court. Huan further alienated the bureaucracy when he initiated grandiose construction projects and hosted thousands of concubines in his harem at a time of economic crisis. Palace eunuchs imprisoned the official Li Ying ( 李膺 ) and his associates from

16256-621: Was to distort the Witwatersrand basin in such a way that the gold-bearing rocks were brought to the present erosion surface in Johannesburg , on the Witwatersrand , just inside the rim of the original 300 km (190 mi) diameter crater caused by the meteor strike. The discovery of the deposit in 1886 launched the Witwatersrand Gold Rush . Some 22% of all the gold that is ascertained to exist today on Earth has been extracted from these Witwatersrand rocks. Much of

16384-399: Was troubled about the abundant Han-manufactured iron weapons traded to the Xiongnu along the northern borders, and he established a trade embargo against the group. In retaliation, the Xiongnu invaded what is now Shanxi , where they defeated the Han forces at Baideng in 200 BC. After negotiations, the heqin agreement in 198 BC nominally held the leaders of the Xiongnu and

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