Jia Dan

Jia Dan

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Jia Dan (730 – October 27, 805), courtesy name Dunshi (敦詩), formally Duke Yuanjing of Wei (魏元靖公), was a Chinese
Han Chinese
Han Chinese are an ethnic group native to China and are the largest single ethnic group in the world.Han Chinese constitute about 92% of the population of the People's Republic of China , 98% of the population of the Republic of China , 78% of the population of Singapore, and about 20% of the...

 scholar-official, general, geographer
Chinese geography
Native Chinese geography begins in the Warring States period . It expands its scope beyond the Chinese homeland with the growth of the Chinese Empire under the Han Dynasty...

, and cartographer from Cangzhou
Cangzhou
Cangzhou is a prefecture-level city in Hebei province, People's Republic of China. Cangzhou's urban center has a population of approximately 514,074 at the 2010 census which correspond to the built up area), while the prefecture-level administrative region in total has a population of 7,134,053...

, Hebei
Hebei
' is a province of the People's Republic of China in the North China region. Its one-character abbreviation is "" , named after Ji Province, a Han Dynasty province that included what is now southern Hebei...

 during the Tang Dynasty
Tang Dynasty
The Tang Dynasty was an imperial dynasty of China preceded by the Sui Dynasty and followed by the Five Dynasties and Ten Kingdoms Period. It was founded by the Li family, who seized power during the decline and collapse of the Sui Empire...

 of China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

.

Background


Jia Dan was born in 730, during the reign of Emperor Xuanzong
Emperor Xuanzong of Tang
Emperor Xuanzong of Tang , also commonly known as Emperor Ming of Tang , personal name Li Longji , known as Wu Longji from 690 to 705, was the seventh emperor of the Tang dynasty in China, reigning from 712 to 756. His reign of 43 years was the longest during the Tang Dynasty...

. His family was from Cang Prefecture (滄州, in modern Cangzhou
Cangzhou
Cangzhou is a prefecture-level city in Hebei province, People's Republic of China. Cangzhou's urban center has a population of approximately 514,074 at the 2010 census which correspond to the built up area), while the prefecture-level administrative region in total has a population of 7,134,053...

, Hebei
Hebei
' is a province of the People's Republic of China in the North China region. Its one-character abbreviation is "" , named after Ji Province, a Han Dynasty province that included what is now southern Hebei...

) and traced its ancestry to the Han Dynasty
Han Dynasty
The Han Dynasty was the second imperial dynasty of China, preceded by the Qin Dynasty and succeeded by the Three Kingdoms . It was founded by the rebel leader Liu Bang, known posthumously as Emperor Gaozu of Han. It was briefly interrupted by the Xin Dynasty of the former regent Wang Mang...

 official Jia Yi
Jia Yi
Jia Yi was a Chinese poet and statesman of the Han Dynasty.- Life:Jia Yi was born in 201 BCE in Luoyang....

, through officials of Cao Wei
Cao Wei
Cao Wei was one of the states that competed for control of China during the Three Kingdoms period. With the capital at Luoyang, the state was established by Cao Pi in 220, based upon the foundations that his father Cao Cao laid...

, Jin Dynasty (265-420)
Jìn Dynasty (265-420)
The Jìn Dynasty , was a dynasty in Chinese history, lasting between the years 265 and 420 AD. There are two main divisions in the history of the Dynasty, the first being Western Jin and the second Eastern Jin...

, Liu Song, Southern Qi
Southern Qi
The Southern Qi Dynasty was the second of the Southern dynasties in China, followed by the Liang Dynasty. During its 23-year history, the dynasty was largely filled with instability, as after the death of the capable Emperor Gao and Emperor Wu, Emperor Wu's grandson Xiao Zhaoye was assassinated...

, Liang Dynasty
Liang Dynasty
The Liang Dynasty , also known as the Southern Liang Dynasty , was the third of the Southern dynasties in China and was followed by the Chen Dynasty...

, Northern Qi
Northern Qi
The Northern Qi Dynasty was one of the Northern dynasties of Chinese history and ruled northern China from 550 to 577.-History:The Chinese state of Northern Qi was the successor state of the Chinese/Xianbei state of Eastern Wei and was founded by Emperor Wenxuan...

, Northern Zhou
Northern Zhou
The Northern Zhou Dynasty followed the Western Wei, and ruled northern China from 557 to 581. It was overthrown by the Sui Dynasty.Northern Zhou's basis of power was established by Yuwen Tai, who was paramount general of Western Wei, following the split of Northern Wei into Western Wei and...

, Sui Dynasty
Sui Dynasty
The Sui Dynasty was a powerful, but short-lived Imperial Chinese dynasty. Preceded by the Southern and Northern Dynasties, it ended nearly four centuries of division between rival regimes. It was followed by the Tang Dynasty....

, and Tang Dynasty
Tang Dynasty
The Tang Dynasty was an imperial dynasty of China preceded by the Sui Dynasty and followed by the Five Dynasties and Ten Kingdoms Period. It was founded by the Li family, who seized power during the decline and collapse of the Sui Empire...

. Both his grandfather Jia Zhiyi (賈知義) and father Jia Yuanyan (賈元琰) served as county-level officials.

Early career


During Emperor Xuanzong's Tianbao era (742-756), Jia Dan passed the imperial examination
Imperial examination
The Imperial examination was an examination system in Imperial China designed to select the best administrative officials for the state's bureaucracy. This system had a huge influence on both society and culture in Imperial China and was directly responsible for the creation of a class of...

s and was made the sheriff of Linqing County (臨清, in modern Liaocheng
Liaocheng
Liaocheng , also known as the Water City, is a prefecture-level city in western Shandong province, People's Republic of China. It borders the provincial capital of Jinan to the southeast, Dezhou to the northeast, Tai'an to the south, and the province of Hebei and Henan to the west...

, Shandong
Shandong
' is a Province located on the eastern coast of the People's Republic of China. Shandong has played a major role in Chinese history from the beginning of Chinese civilization along the lower reaches of the Yellow River and served as a pivotal cultural and religious site for Taoism, Chinese...

). After he submitted suggestions on the matters of the times to Emperor Xuanzong, he was moved to be the sheriff of Zhengping County (正平, in modern Yuncheng, Shanxi
Shanxi
' is a province in Northern China. Its one-character abbreviation is "晋" , after the state of Jin that existed here during the Spring and Autumn Period....

) — closer to the capital Chang'an
Chang'an
Chang'an is an ancient capital of more than ten dynasties in Chinese history, today known as Xi'an. Chang'an literally means "Perpetual Peace" in Classical Chinese. During the short-lived Xin Dynasty, the city was renamed "Constant Peace" ; yet after its fall in AD 23, the old name was restored...

, and therefore considered a promotion despite it being the same level of office. While the general Wang Sili (王思禮) served as the military governor (Jiedushi
Jiedushi
The Jiedushi were regional military governors in China during the Tang Dynasty and the Five Dynasties and Ten Kingdoms Period. Originally set up to counter external threats, the jiedushi were given enormous power, including the ability to maintain their own armies, collect taxes, and pass their...

) of Hedong Circuit (河東, headquartered in modern Taiyuan
Taiyuan
Taiyuan is the capital and largest city of Shanxi province in North China. At the 2010 census, it had a total population of 4,201,591 inhabitants on 6959 km² whom 3,212,500 are urban on 1,460 km². The name of the city literally means "Great Plains", referring to the location where the Fen River...

, Shanxi
Shanxi
' is a province in Northern China. Its one-character abbreviation is "晋" , after the state of Jin that existed here during the Spring and Autumn Period....

), Wang invited him to serve as secretary. While serving under Wang, Jia was promoted to be the deputy mayor of Taiyuan Municipality and deputy military governor. He later served as the prefect of Fen Prefecture (汾州, in modern Linfen
Linfen
-Administrative divisions:The prefecture-level city of Linfen is divided in one district, two cities and fourteen counties. The information here presented uses the metric system and data from 2010 Census.-Pollution:...

, Shanxi
Shanxi
' is a province in Northern China. Its one-character abbreviation is "晋" , after the state of Jin that existed here during the Spring and Autumn Period....

) for seven years and was known for ruling the prefecture well.

Jia was then recalled to Chang'an to serve as the minister of vassal affairs (鴻臚卿, Honglu Qing), which included the responsibilities of receiving and entertaining foreign emissaries, as well as imperial funerals and the command of two units of the imperial guards, the Weiyuan Camp (威遠營). As the minister of vassal affairs, he would havemet with foreign envoys in order to acquire information about their native countries. This included cultural customs as well as geographic information, as a map was drawn after the geographic information was acquired from the interview. Historian Edward Schafer states that it is no doubt that Jia's remarkable knowledge of foreign geography was derived from these interviews with foreign delegates and diplomats. In 779, during the reign of Emperor Xuanzong's grandson Emperor Daizong
Emperor Daizong of Tang
Emperor Daizong of Tang , personal name Li Yu , né Li Chu , was an emperor of the Chinese Tang Dynasty....

, Jia was made the prefect of Liang Prefecture (梁州, in modern Hanzhong
Hanzhong
Hanzhong is a municipality in southwest Shaanxi Province, China, occupying a historically significant valley in the mountains between the Xi'an area, home to many Chinese capitals, and the fertile but isolated Sichuan Basin...

, Shaanxi
Shaanxi
' is a province in the central part of Mainland China, and it includes portions of the Loess Plateau on the middle reaches of the Yellow River in addition to the Qinling Mountains across the southern part of this province...

) and the military governor of Shannan West Circuit (山南西道, headquartered at Liang Prefecture).

During Emperor Dezong's reign


In 781, during the reign of Emperor Daizong's son Emperor Dezong
Emperor Dezong of Tang
Emperor Dezong of Tang , personally name Li Kuo , was an emperor of the Chinese Tang Dynasty and the oldest son of his father Emperor Daizong. His reign of 26 years was the third longest in the Tang dynasty...

, when Liang Chongyi
Liang Chongyi
Liang Chongyi was a general of the Chinese dynasty Tang Dynasty. During the reign of Emperor Daizong, Liang took advantage of the army's discontent after the death of the general Lai Tian to seize control of Shannan East Circuit and hold it semi-independently from the imperial regime...

, the military governor of nearby Shannan East Circuit (山南東道, headquartered in modern Xiangfan
Xiangfan
Xiangyang is a prefecture-level city in Hubei Province of the People's Republic of China. It was formed from two famous ancient cities, Xiangyang and Fancheng...

, Hubei
Hubei
' Hupeh) is a province in Central China. The name of the province means "north of the lake", referring to its position north of Lake Dongting...

), rebelled against Emperor Dezong's rule, Jia Dan participated in the campaign against Liang and captured Jun Prefecture (均州, in modern Shiyan
Shiyan
Shiyan is a prefecture-level city in northwestern Hubei province, People's Republic of China.-Geography:The Wudang Mountains run approximately east-west through the territory of the "Prefecture-level city" of Shiyan, crossing several of its county-level divisions...

, Hubei
Hubei
' Hupeh) is a province in Central China. The name of the province means "north of the lake", referring to its position north of Lake Dongting...

). In 782, after Liang's defeat and suicide, Jia was made the military governor of Shannan East Circuit, and in 783 participated in the campaign against another rebel general, Li Xilie
Li Xilie
Li Xilie was a general of the Chinese Tang Dynasty who, believing himself to be strong enough to claim imperial title, did so as the emperor of a new state of Chu...

 the military governor of Huaixi Circuit (淮西, headquartered in modern Zhumadian
Zhumadian
Zhumadian is a prefecture-level city in southern Henan province, People's Republic of China. It borders Xinyang to the south, Nanyang to the west, Pingdingshan to the northwest, Luohe to the north, Zhoukou to the northeast, and the province of Anhui to the east.Its population is 7,230,744 at the...

, Henan
Henan
Henan , is a province of the People's Republic of China, located in the central part of the country. Its one-character abbreviation is "豫" , named after Yuzhou , a Han Dynasty state that included parts of Henan...

.

In 784, while Emperor Dezong was at Liang Prefecture after he fled there due to rebellions by the general Zhu Ci
Zhu Ci
Zhu Ci was a general of the Chinese dynasty Tang Dynasty. He initially served as military governor of Lulong Circuit , but later became a general for the imperial government...

 and Li Huaiguang
Li Huaiguang
Li Huaiguang was a leading general of the Chinese dynasty Tang Dynasty, of Mohe extraction. He was credited with saving Emperor Daizong in the face of an attack by the rebel Zhu Ci in 783 but, dissatisfied with the lack of trust that Emperor Dezong displayed in him later, also rebelled, but his...

, there was an occasion when Jia sent his officer Fan Ze (樊澤) to make reports to Emperor Dezong. After Fan's return, there was suddenly an imperial edict issued making Fan the military governor of Shannan East Circuit and recalling Jia to Emperor Dezong's location to serve as the minister of public works (工部尚書, Gongbu Shangshu). When the edict arrived, Jia was hosting a feast, and he received the edict as if nothing had happened. After the feast was over, he informed Fan of his promotion and immediately began the transition, including having the other officers greet Fan as their new superior. The officer Zhang Xianfu (張獻甫) was angered, believing that Fan had treacherously seized Jia's position, and he wanted to kill Fan. Jia stopped him, pointing out that because Fan had imperial sanction, he was the proper military governor. That same day, he left his post and headed for the emperor's location, taking Zhang with him to avoid any further disturbance. Jia was soon made the defender of the eastern capital Luoyang
Luoyang
Luoyang is a prefecture-level city in western Henan province of Central China. It borders the provincial capital of Zhengzhou to the east, Pingdingshan to the southeast, Nanyang to the south, Sanmenxia to the west, Jiyuan to the north, and Jiaozuo to the northeast.Situated on the central plain of...

.

In 785, Jia completed a map of China and her former colonies in Central Asia
Central Asia
Central Asia is a core region of the Asian continent from the Caspian Sea in the west, China in the east, Afghanistan in the south, and Russia in the north...

 that were lost to the Uyghurs
Uyghur people
The Uyghur are a Turkic ethnic group living in Eastern and Central Asia. Today, Uyghurs live primarily in the Xinjiang Uyghur Autonomous Region in the People's Republic of China...

 and Tibet
Tibet
Tibet is a plateau region in Asia, north-east of the Himalayas. It is the traditional homeland of the Tibetan people as well as some other ethnic groups such as Monpas, Qiang, and Lhobas, and is now also inhabited by considerable numbers of Han and Hui people...

ans. Upon its completion in 801, the map was 9.1 m (30 ft) in length and 10 m (33 ft) in height, mapped out on a grid scale of one inch equaling one hundred li
Li (unit)
The li is a traditional Chinese unit of distance, which has varied considerably over time but now has a standardized length of 500 meters or half a kilometer...

(Chinese unit of measuring distance).

In 786, after the death of Li Cheng (李澄) the military governor of Yicheng Circuit (義成, headquartered in modern Anyang
Anyang
Anyang is a prefecture-level city in Henan province, People's Republic of China. The northernmost city in Henan, Anyang borders Puyang to the east, Hebi and Xinxiang to the south, and the provinces of Shanxi and Hebei to its west and north respectively....

, Henan
Henan
Henan , is a province of the People's Republic of China, located in the central part of the country. Its one-character abbreviation is "豫" , named after Yuzhou , a Han Dynasty state that included parts of Henan...

), Jia was made the military governor of Yicheng. At that time, Li Na
Li Na (Tang Dynasty)
Li Na , formally the Prince of Longxi , was a general of the Chinese Tang Dynasty. Inheriting the post from his father Li Zhengji, he served as the military governor of Pinglu Circuit semi-independently from the imperial government.- Background :Li Na was born in 758, during the reign of...

 the military governor of neighboring Pinglu Circuit (平盧, headquartered in modern Tai'an
Tai'an
Tai'an is a prefecture-level city in western Shandong province, People's Republic of China.Centered around Mount Tai, the city borders the provincial capital of Jinan to the north, Laiwu to the northeast, Zibo to the east, Linyi to the southeast, Liaocheng to the extreme west and Jining to the south...

, Shandong
Shandong
' is a Province located on the eastern coast of the People's Republic of China. Shandong has played a major role in Chinese history from the beginning of Chinese civilization along the lower reaches of the Yellow River and served as a pivotal cultural and religious site for Taoism, Chinese...

), who had previously rebelled against Emperor Dezong but later resubmitted (albeit nominally), was still viewed as a threat to the circuits loyal to the imperial regime. On an occasion, when Pinglu soldiers, returning from a posting to the western border with Tufan, were going through Yicheng on the way back to Pinglu, Jia's subordinates, worried that they might act against Yicheng, suggested that they be kept outside the city walls of Yicheng's headquarters Hua Prefecture (滑州). Jia, reasoning that it was improper to let soldiers from a neighboring circuit rest in the open air, welcomed them inside, and the Pinglu soldiers did not dare to create any disturbance. Jia also often hunted on the borders with Pinglu, often venturing into Pinglu territory. When Li Na received these reports, he was pleased that Jia did not consider him hostile and admired Jia for his openness, and therefore did not carry out any hostile actions against Yicheng.

In 793, Jia was recalled to Chang'an to serve as You Pushe (右僕射), one of the heads of the executive bureau of government (尚書省, Shangshu Sheng). He was also given the designation Tong Zhongshu Menxia Pingzhangshi (同中書門下平章事), making him a chancellor, serving with Lu Zhi (Tang Dynasty)
Lu Zhi (Tang Dynasty)
Lu Zhi , courtesy name Jingyu , was an official of the Chinese Tang Dynasty, serving as a chancellor during the reign of Emperor Dezong. Even before he became chancellor, he became a trusted advisor to Emperor Dezong, who greatly valued his opinion...

, Zhao Jing
Zhao Jing (Tang Dynasty)
Zhao Jing , courtesy name Tuiweng , was an official of the Chinese dynasty Tang Dynasty, serving as a chancellor during the reign of Emperor Dezong.- Background :...

, and Lu Mai
Lu Mai
Lu Mai , courtesy name Zixuan , was an official of the Chinese dynasty Tang Dynasty, serving as a chancellor during the reign of Emperor Dezong.- Background :Lu Mai was born in 739, during the reign of Emperor Xuanzong...

.

In 800, when Lu Qun (盧群) the military governor of Yicheng died, Jia Dan advocated that Emperor Dezong commission a military governor without first consulting the officers of the circuit, believing that such consultation showed weakness. Emperor Dezong agreed and directly made the official Li Yuansu (李元素) the military governor of Yicheng. In 801, Jia completed a 40-volume work that included a large map of the Chinese
Chinese people
The term Chinese people may refer to any of the following:*People with Han Chinese ethnicity ....

 and the non-Chinese populations, and descriptions of the various circuits of Tang as well as foreign nations (see further below). Emperor Dezong awarded him with a number of silk and silver items, as well as a horse, and created him the Duke of Wei.

During Emperor Shunzong's and Xianzong's reigns


In 805, Emperor Dezong died, and his severely ill son Li Song
Emperor Shunzong of Tang
Emperor Shunzong of Tang , personal name Li Song , was an emperor of the Chinese Tang Dynasty. He was created crown prince in 779 and became emperor in 805 after the death of his father Emperor Dezong, of whom he was the oldest son...

 became emperor (as Emperor Shunzong). Emperor Shunzong's close associate Wang Shuwen
Wang Shuwen
Wang Shuwen was an official of the Chinese dynasty Tang Dynasty. He was a close associate of Emperor Shunzong while Li Song was crown prince under his father Emperor Dezong, and was powerful during Emperor Shunzong's brief reign in 805, when Emperor Shunzong was severely ill...

 became the most powerful figure at court, despite his not being a chancellor, and Wang's associates became in charge of many important matters. Jia Dan disliked Wang and his associates and thus offered to retire, but Emperor Shunzong did not approve of the retirement. JIa died later that year, after Emperor Shunzong had passed the throne to his son Li Chun
Emperor Xianzong of Tang
Emperor Xianzong of Tang , personal name Li Chun , né Li Chun , was an emperor of the Chinese Tang Dynasty...

 (as Emperor Xianzong) and was given posthumous honors. It was said that during JIa's service as chancellor, while he had no major contributions on policy matters, he was virtuous and led by example.

Written works


In the 40-volume work that Jia completed in 801, Jia wrote of two common sea trade routes in his day: one from the coast of the Bohai Sea
Bohai Sea
Bohai Sea , also known as Bohai Gulf, Bohai, or Bo Hai, is the innermost gulf of the Yellow Sea on the coast of Northeastern and North China. It is approximately 78,000 km2 Bohai Sea , also known as Bohai Gulf, Bohai, or Bo Hai, is the innermost gulf of the Yellow Sea on the coast of...

 towards Silla
Silla
Silla was one of the Three Kingdoms of Korea, and one of the longest sustained dynasties in...

 in Korea
Korea
Korea ) is an East Asian geographic region that is currently divided into two separate sovereign states — North Korea and South Korea. Located on the Korean Peninsula, Korea is bordered by the People's Republic of China to the northwest, Russia to the northeast, and is separated from Japan to the...

 and another from Guangzhou through Malacca
Malacca
Malacca , dubbed The Historic State or Negeri Bersejarah among locals) is the third smallest Malaysian state, after Perlis and Penang. It is located in the southern region of the Malay Peninsula, on the Straits of Malacca. It borders Negeri Sembilan to the north and the state of Johor to the south...

 towards the Nicobar Islands
Nicobar Islands
The Nicobar Islands are an archipelagic island chain in the eastern Indian Ocean...

, Sri Lanka
Sri Lanka
Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka is a country off the southern coast of the Indian subcontinent. Known until 1972 as Ceylon , Sri Lanka is an island surrounded by the Indian Ocean, the Gulf of Mannar and the Palk Strait, and lies in the vicinity of India and the...

 and India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

, the eastern and northern shores of the Arabian Sea
Arabian Sea
The Arabian Sea is a region of the Indian Ocean bounded on the east by India, on the north by Pakistan and Iran, on the west by the Arabian Peninsula, on the south, approximately, by a line between Cape Guardafui in northeastern Somalia and Kanyakumari in India...

 to the Euphrates River. Indeed, Korean vessels dominated the Yellow Sea
Yellow Sea
The Yellow Sea is the name given to the northern part of the East China Sea, which is a marginal sea of the Pacific Ocean. It is located between mainland China and the Korean Peninsula. Its name comes from the sand particles from Gobi Desert sand storms that turn the surface of the water golden...

 trade, while most Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

ese vessels were forced to venture towards the mouth of the Huai River
Huai River
The Huai River is a major river in China. The Huai River is located about mid-way between the Yellow River and Yangtze River, the two largest rivers in China, and like them runs from west to east...

 and Yellow River
Yellow River
The Yellow River or Huang He, formerly known as the Hwang Ho, is the second-longest river in China and the sixth-longest in the world at the estimated length of . Originating in the Bayan Har Mountains in Qinghai Province in western China, it flows through nine provinces of China and empties into...

, and even as far south as Hangzhou Bay
Hangzhou Bay
Hangzhou Bay, or the Bay of Hangzhou , is an inlet of the East China Sea, bordered by the province of Zhejiang and the municipality of Shanghai. The Qiantang River flows into the bay.It lies south of Shanghai, and ends at the city of Hangzhou...

. Jia wrote that the ships in the Euphrates had to anchor at the mouth of the Euphrates and transfer the trade goods on land towards the capital (Baghdad
Baghdad
Baghdad is the capital of Iraq, as well as the coterminous Baghdad Governorate. The population of Baghdad in 2011 is approximately 7,216,040...

) of Dashi Guo (Abbasid
Abbasid
The Abbasid Caliphate or, more simply, the Abbasids , was the third of the Islamic caliphates. It was ruled by the Abbasid dynasty of caliphs, who built their capital in Baghdad after overthrowing the Umayyad caliphate from all but the al-Andalus region....

). This was confirmed by the contemporary Arab merchant Shulama, who noted that the draft in Chinese junk ships
Junk (ship)
A junk is an ancient Chinese sailing vessel design still in use today. Junks were developed during the Han Dynasty and were used as sea-going vessels as early as the 2nd century AD. They evolved in the later dynasties, and were used throughout Asia for extensive ocean voyages...

 were too deep to enter the Euphrates, forcing them to land passengers and cargo ashore on smaller boats. A small branch of this extensive second trade route led all the way to Dar es Salaam
Dar es Salaam
Dar es Salaam , formerly Mzizima, is the largest city in Tanzania. It is also the country's richest city and a regionally important economic centre. Dar es Salaam is actually an administrative province within Tanzania, and consists of three local government areas or administrative districts: ...

 in Tanzania
Tanzania
The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...

, East Africa
East Africa
East Africa or Eastern Africa is the easterly region of the African continent, variably defined by geography or geopolitics. In the UN scheme of geographic regions, 19 territories constitute Eastern Africa:...

. In his work written between 785 and 805, he described the sea route going into the mouth of the Persian Gulf
Persian Gulf
The Persian Gulf, in Southwest Asia, is an extension of the Indian Ocean located between Iran and the Arabian Peninsula.The Persian Gulf was the focus of the 1980–1988 Iran-Iraq War, in which each side attacked the other's oil tankers...

, and that the medieval Iranian
Iranian peoples
The Iranian peoples are an Indo-European ethnic-linguistic group, consisting of the speakers of Iranian languages, a major branch of the Indo-European language family, as such forming a branch of Indo-European-speaking peoples...

s (whom he called the people of Luo-He-Yi) had erected 'ornamental pillars' in the sea that acted as lighthouse
Lighthouse
A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses or, in older times, from a fire, and used as an aid to navigation for maritime pilots at sea or on inland waterways....

 beacons for ships that might go astray. Confirming Jia's reports about lighthouses in the Persian Gulf, Arabic writers a century after Jia wrote of the same structures, writers such as al-Mas'udi and al-Muqaddasi
Al-Muqaddasi
Muhammad ibn Ahmad Shams al-Din Al-Muqaddasi , also transliterated as Al-Maqdisi and el-Mukaddasi, was a medieval Arab geographer, author of Ahsan at-Taqasim fi Ma`rifat il-Aqalim .-Biography:Al-Muqaddasi, "the Hierosolomite" was born in Jerusalem in 946 AD...

.