Cai Lun

Cai Lun (; courtesy name: Jingzhong (); – 121 CE), formerly romanized as Ts'ai Lun, was a Chinese eunuch court official of the Eastern Han dynasty. He is traditionally regarded as the inventor of paper and the modern papermaking process, as he originated paper in its modern form. Although early forms of paper had existed since at least the 3rd century BCE, he occupies a pivotal place in the history of paper due to his addition of important new materials, such as tree bark and hemp ends, which resulted in the large-scale manufacture and rapid spread of paper.
Born in Leiyang county, (modern-day Leiyang, Hunan), Cai arrived at the imperial court in (modern-day Luoyang, Henan) by 75, where he served as a chamberlain for Emperor Ming, and then a imperial messenger () for Emperor Zhang. To assist Lady Dou in securing her adopted son as designated heir, he interrogated Consort Song and her sister, who then killed themselves. When Emperor He ascended the throne in 88, Dou awarded Cai with two positions; first—the highest position for eunuch of the time—a political counselor () to the emperor, and soon after the additional post as a "Prefect of the Palace Workshop" (), where Cai oversaw the production of instruments and weapons for imperial use. 
Despite Emperor He’s successful 92 coup d'état against the Dou family, Cai was undisturbed by his former ally's downfall. His position in the Palace Workshop increased in scope; he became responsible for the production of ceremonial weapons, which the reports were of exemplary craftsman ship. However, Cai's most noted product was in 105, when he substantially improved the papermaking process with the use of tree bark, hemp waste, old rags, and fishnets. His new type of paper quickly surpassed the predominate bamboo and wooden slips in popularity, and Cai received wealth and fame throughout the empire. In 110, Lady Deng, who had become dowager empress under the young Emperor An, appointed Cai to oversee 100 scholars' new edition of the Five Classics. She awarded Cai for his imperial service in 114; he received the title of "marquis", and was enfeoffed lordship of , a small village. When his ally Deng died in 121, he was ordered to death due to both a false rumor that he intended to harm the emperor, and his previous involvement in the death of the emperor's grandmother, Consort Song. Ashamed at his predicament, he committed suicide that year, and died in the capital city in which he had spent virtually his entire adult life.
Cai's papermaking efforts are considered enormously impactful on human history and of China's Four Great Inventions—the compass, gunpowder, papermaking and printing—Cai is the only inventor whose name is known. While in China he is revered in ancestor worship, the subject of folklore and deified as the god of papermaking, he is mostly unknown outside of East Asia. His hometown in Leiyang remains an active center of paper production. 
Sources.
The main source of information on Cai Lun's is just 300 characters in volume 78 of the (; "Book of the Later Han"), an official history compiled by the Liu Song dynasty historian and politician Fan Ye. The modern sinologist Tsien Tsuen-hsuin, noted that while Fan's account is the most comprehensive, it is problematic due to being written nearly 300 years after Cai's death. The primary source Fan used was the 2nd-century "" (; "History of the Eastern Han"), in which is credited as the author of Cai's biography. Yan's brief 70 character account is near-contemporary but only survives in a reconstructed state from a lost original. Another older source is a brief mention by the 3rd-century scholar, Tung Pa, who is quoted referencing Cai papermaking accomplishments in the 10th-century "leishu" encyclopedia (; "Readings of the Taiping Era"). 
Later histories, such as the Song dynasty ' (; "Compound Source of Matters and Facts"), include Cai and his work with papermaking as well. However, there are various major histories, such as the ' (; "Annals of the Later Han") and "" (; "Comprehensive Mirror in Aid of Governance") that do not make reference to Cai's papermaking achievements. Sinologist T H Barrett suggested this was because "Cai Lun was, after all, a palace eunuch, precisely the sort of person normally viewed with antagonism by the regular bureaucrats who controlled the writing of official (and even most unofficial) history".
Life and career.
Birth and background.
Cai Lun was born in Leiyang county, (; modern-day, Leiyang, Hunan province) during the mid 1st-century CE of the Eastern Han dynasty (25–220 CE). His exact year of birth is unknown; estimates include , , and . Other than being born into a poor family, virtually nothing is known of his early life. Guiyang was a southern commandary, where Han Chinese migrants had immigrated to for hundreds of years to plant and cultivate rice. Legends suggest there was a pool near his home, south of which was a stone mortar that Cai would later use for papermaking.
Early imperial court service.
It is not known how Cai Lun came to be in the service of the imperial court in (modern-day Luoyang, Henan province), which was distant from his birthplace. The reports that he was first employed toward the end of the era (58–75) of Emperor Ming. The site of modern Leiyang was known to have had various iron mines at the time, so the former director of the in Tokyo, Kiyofusa Narita, suggested that "through the assistance of some who were in charge of the iron foundry, he found opportunity to go to the capital city". Narita cited Cai's future court appointment to oversee the production of weapons, especially swords, as evidence that he must have learned the skills to do so earlier in his life, likely from the iron foundry. Alternatively, if there is any truth to the various folktales about Cai, his supposed habits of trickery may have helped him receive a court appointment.
Cai is known to have been a castrated eunuch in 75, although it is possible he was employed somewhat earlier in the era; sinologist Rafe de Crespigny suggested this was in the early 70s. In the Han dynasty, eunuchs were employed in imperial service and were the only people eligible for certain specialized tasks, such as watching over the imperial harem and the imperial household; there were also certain promotions available for them. Cai's position was probably as a liaison between the privy council and the emperor, and likely involved duties akin to a chamberlain for the royal family. Narita notes Cai's role meant he would have had many chances to become acquainted with the most powerful people in the empire. During the subsequent era (76–84) under Emperor Zhang, Cai was promoted around 80 to a (; "Attendent at the Yellow Gates"). This position, of a salary-rank of 600 "shi" or "dan", involved delivering and receiving messages between the imperial palace apartments and the outside court.
Palace intrigue and workshop.
Since 82, Liu Qing, Zhang's son from his concubine Consort Song, had been the designated heir, secured from the favor of Empress Ma. However, Ma's death in 79, made Lady Dou the empress, and—aiming to develop her family's power—she adopted Prince Zhao, with the intention of instilling him as heir. As a result, when Consort Song became ill in 82 and asked for herbs, Empress Dou falsely accused her of planning to use the herbs for witchcraft against Zhang. Dou then ordered Cai Lun to interrogate Consort Song and her sister, another imperial consort, in order to force a confession; they both killed themselves. Believing Dou's accusation, Zhang replaced Liu Qing with Prince Zhao as heir.
Prince Zhao, ruling as Emperor He, was 10 years old at his accession in 88, so Dou took control as empress dowager and secured her authority by giving various positions to her four brothers, particularly Dou Xian. Because of his loyalty, Dou promoted Cai to (; "Regular Attendant"), where he served as a private counselor to He in political matters. This post gave Cai a high salary-rank of 2000 "shi", and was a limited position only eunuchs were eligible—and the highest they could hold, which also made him a chief eunuch of the palace. In the , Cai was characterized as, in the words of de Crespigny, "honest, cautious and a good judge of policy". Cai gained the additional role of (; "Prefect of the Palace Workshop" or "Prefect of the Masters of Techniques") later in 88, or in 89. Also a eunuch-only position, he would have been responsible for the production of instruments and weapons for imperial use. The role had a salary-rank of 600 "shi"—though this was in addition to 2000 "shi" from his continued post.
When Emperor He came of age in 92 he led various officials, especially Zheng Zhong, in a coup d'état to overthrow the Dou family. Cai was not involved in their removal, and though he was previously allied with the family, he was undistributed by the Emperor's coup. In 97, his position expanded in scope, as he became responsible for ceremonial swords and other items. The describes his craftsmanship as that of especially high-quality and a model for later generations.
Development of paper.
In 105, Cai Lun publicly declared that he had invented a new composition for paper with a new papermaking process. Writing had a long history in China with writing surfaces being bamboo and wooden slips (wood for short text and bamboo for lengthy text). These media were inconvenient as they were awkward to store as well as heavy and difficult to write on. After the creating of a writing animal-hair brush by Meng Tian in the 3rd-century BCE, silk and cloth became alternatives that addressed these issues, but they were too expensive to enable widespread use. The absence of a practical solution motivated continued experimentation with different materials; Cai's pulp solution became the most effective in 105. Cai's process still involved the use of bamboo but also hemp waste, old rags, fishnets and most importantly, bark from trees, probably mulberry ones. These materials were boiled in a pulp that was beaten with a wood or stone mallet and then mixed with a large amount of water. The resulting composition was then dunked with wooden sieves and the excess water was removed, leaving the paper finished after drying. The paper that resulted form this method is often referred to as "Cai Hou paper" (). This event and its context are relayed in an often cited passage of the :
Many legends exist as to the inspiration for Cai's invention; among the most popular is that Cai was inspired by watching paper wasps make their nests. Tsien suggested that Cai was inspired by the people of his birthplace, who used bark from the many mulberry trees to create cloth as a writing surface. Irrespective of its origin, in 105, Cai's new paper making process both impressed He and gained him fame throughout the empire.
Final years and death.
In 106—after the infant Emperor Shang's eight month reign—Emperor He was succeeded by 13 year-old Emperor An, where Lady Deng, ruled as empress dowager. Both Cai and Zheng maintained influence in Dowager Deng's court. In 110, Deng assembled more than 100 scholars—including , and Ma Rong—in the Eastern Pavilion of the palace to begin creating a definitive edition of the Five Classics. She appointed Cai to oversee and supervise the production; de Crespigny said that this meant Cai "was seriously concerned with scholarship". In 114, he was awarded the title of "marquis" and enfeoffed him as the lord of , a small village of 300 families, in modern-day Yang County, Shaanxi. Later that year, Zheng Zhong died and Cai succeeded him as the head of the Dowager's houshold.
After Deng's death in 121, An assumed power, though the court was dominated by the influence of Empress Yan Ji and her brothers. An had not forgotten Cai's part in the death of his mother, Consort Song, and ordered him to reported to the Ministry of Justice in order to answer the charges—presumably death. Cai, ashamed that the Emperor would send him to death in a dishonorable way, bathed and dressed in formal clothes, before killing himself by drinking the poison. Cai's death date and place are unknown, but various monuments and shrines have been erected to honor him.
Legacy.
Global influence.
Historical assessment.
Due to modern archeological investigations, it is now certain that different forms of paper existed in China as early as the 3rd-century BCE. However, Tsien noted that this does not necessarily discount the credit given to Cai. Tsien explains that the term used in Cai's ancient biography, "tsao i", can be understood as "to initiate the idea", meaning that he furthered the ongoing process with the addition of important materials. Additionally, Cai is responsible for the earliest known use of tree bark and hemp as ingredients for paper, and it is clear that paper did not see wide-spread use in China until Cai's improvements. As such, scholars have revised his contributions as ones that furthered an ongoing process, rather than a sudden discovery, However, due to the pivotal significance of his improvements and the resulting rapid spread of paper-use throughout China, Cai Lun continues to be traditionally credited with inventing paper. There is also speculation Cai was the patron of this achievement and took credit from someone else, as Feng Dao may have done with his improvements to printing.
Spread of paper.
Cai Lun's improvements to paper and the paper making process are considered enormously impactful to human history, spreading literature and knowledge around the world as well as revolutionizing the means of communication. However, Cai is only somewhat known outside East Asia and is often excluded from major encyclopedias. The scholar of paper history, Thomas Francis Carter, has drawn parallels between Cai and Johannes Gutenberg, the inventor of the movable type printing press, calling them "spiritual father and son" respectively. In his 1978 book, "", author Michael H. Hart ranked him 7th, above figures such as Gutenberg, Christopher Columbus, Albert Einstein and Charles Darwin. In 2007, "Time" ranked him as among the "Best Inventors" of all time.
After Cai efforts in 105, a renowned paper maker—variously recorded by modern sources as "'Zuo Bo; Tso Po (courtesy name: Tzu-i) from Tung-Hai, Shandong; or Tso Tzǔ-yi"'—who may have been an apprentice to Cai, improved the process in 150, or later in the Han dynasty. Other than this, the basic principles of Cai's papermaking process have changed little over time, and the new form of paper rapidly spread throughout China. According to legend, the Buddhist monk Damjing brought the process to Japan; though this is unconfirmed, Damjing occupies a similar patron saint position in Japan that Cai does in China. By the 600s the process appeared in Turkestan, Korea and India, while Chinese prisoners from the 751 Battle of Talas spread the knowledge to Arabs of the Abbasid Caliphate. Unlike many Chinese inventions that were created independently in Western Europe, the modern paper making process was a wholly Chinese product and gradually spread by the Arabs to Europe, where it also saw widespread manufacturing by the 12th-century. In August 2010, the International Astronomical Union honored Cai's legacy by naming a crater on the Moon after him.
Influence in China.
Folklore.
While Cai's personal life is mostly unknown, a popular folktale suggests he had a wife, brother and was both a shopkeeper and trickster, though there is no historical confirmation to this. The story goes that after Cai's improvements to paper there was little demand for the product so he had an ever-growing surplus. As such, Cai and his wife developed a ploy to increase sales; they told townsfolk that paper becomes money in the afterlife when burned. 
In the most popular variation to the tale, Cai Mo and Hui Niang—Cai's brother and sister-in-law of unconfirmed historicity—take the place of Cai and his wife. In this version, Hui convinced Cai Mo to learn the new papermaking trade from his younger brother, and when he returned in only 3 months, the paper he and his wife produce was too low quality to sell. To address this, Hui pretended to have died, and Cai Mo stood at beside her coffin, wailing and burning money as tribute. Then, their neighbors checked in on them, and Hui sprung out of the coffin, explaining that the burned money was transferred to her in the afterlife, with which she paid ghosts to return her from the dead. Believing the story, the neighbors quickly purchased large amounts of paper for their own use. While mostly fictitious, intense wailing and burning offerings were commonplace in Chinese culture.
Deification and remembrance.
Of China's Four Great Inventions of the ancient world—the compass, gunpowder, papermaking and printing)—only the inventor of papermaking, Cai Lun, is known. Additionally, in comparison to other Chinese inventions such as the writing brush and ink, the development of paper is the best documented in literary sources.
After his death in 121 a shrine with his grave was built in his hometown, but was soon neglected and damaged by floods, while his name was largely forgotten. During the late 7th-century of the Tang dynasty, many national heroes were deified, such as Li Bai and Guan Yu as the gods of wine and war respectively. Cai was among the important people declared gods, being deified as the national god of papermaking. Cai also became a patron saint for papermakers, with his image often being painted or printed onto paper mills and paper shops in not only China, but also Japan. In 1267, a man named Chen Tsunghsi raised funds to repair the long-damaged shrine, and renovated it to include a statue of Cai and a mausoleum. Chen stated that "Tsai Lung's [Cai Lun's] extraordinary talent and his achievement are exemplary to all ages." A stone mortar, which legends claim Cai used to make paper, may have been brought to the mausoleum, although other sources say it was brought to the Imperial Museum in the capital of Lin'an. A great ceremony was held for the new mausoleum, although it eventually fell into ruin again and had to be restored in 1955. Today, the temple still stands in Leiyang as the near a pool, renamed the "Cai Lun Pool", that was thought to be near Cai's home. In the Song dynasty, Fei Chu () said there was a temple in Chengdu where hundreds of families in the papermaking business would come to worship Cai.
During the late Qing dynasty, papermakers created religious groups, known as either "spirit-money associations" () or "Cai Lun associations" (). In 1839, the from the town of Yingjiang, was sued by in Macun and Zhongxing of the Jiajiang County, Sichuan. The conflict had begun when the of Yingjiang claimed that their statue of Cai—which they carried throughout Jiajiang County annually—gave them ritual supremacy over the papermakers of Macun and Zhongxing, whom they demanded pay for and take part in their celebrations. The of Macun and Zhongxing denied the demand, citing their long history of worshipping Cai, which resulted in ever increasing conflict between the sides and eventually a law suit. The county magistrate reproached both parties for descending into conflict and said: "Did they not understand that all of them owed their livelihood to Lord Cai, who had taught them the art of papermaking? Were they not all disciples of Lord Cai, who wanted them to share the benefits of the trade?". 
In the 21st-century, Leiyang is still famous as Cai's birthplace and has active paper production. In modern-day China, Cai's name is closely associated with paper, being the namesake of the Cai Lun Paper Culture Museum, and at least five roads: , Pudong, Shanghai; Cailun road, Minhang District, Shanghai; Cailun Road, Fuyang District, Hangzhou, Zhejiang; Cailun Road East Crossing, Weiyang District, Xi'an; and Cailun Road, Yaohai District, Hefei, Anhui.