Cai Lun

Cai Lun (Chinese: 蔡伦; courtesy name: Jingzhong (敬仲); c. 50–62 – 121 CE), formerly romanized as Ts'ai Lun, was a Chinese eunuch court official of the Eastern Han dynasty. He holds an important place in the history of paper. He added pulp made from tree bark and hemp ends, which led to paper being made on a large scale and spreading around the world. Although Cai is traditionally regarded as the inventor of paper, earlier forms of paper existed from the 3rd century BCE, so his contributions were an innovation rather than an invention.

Cai was born in Guiyang Commandery, in what is now Leiyang. By 75 CE, he had arrived at the imperial court in Luoyang, where he served as a chamberlain for Emperor Ming and then as Xiao Huangmen, an imperial messenger for Emperor Zhang. To help Lady Dou secure her adopted son as designated heir, he interrogated Consort Song and her sister. When Emperor He took the throne in 88 CE, Dou gave Cai two positions. One was a political counselor to the emperor, the highest position for eunuchs of the time. The other was Shangfang Ling, where Cai oversaw the production of instruments and weapons at the Palace Workshop.

Emperor He launched a successful coup d'état against the Dou family in 92 CE, but Cai was not affected by his former ally's downfall. His work at the Palace Workshop grew, and he became responsible for making ceremonial weapons, which the Hou Hanshu reports were of excellent craftsmanship. However, Cai's most famous innovation came in 105 CE, when he greatly improved the papermaking process by using tree bark, hemp waste, old rags, and fishnets. His new paper quickly replaced the bamboo and wooden slips that had been used until then, and Cai received wealth and fame across the empire.

In 110 CE, Lady Deng, who had become the empress dowager to the young Emperor An, appointed Cai to oversee 100 scholars preparing a new edition of the Five Classics. In 114 CE, Cai was rewarded for his imperial service. He received the title of marquis and was enfeoffed as lord of Longting, a small village. When his ally Deng died in 121 CE, Cai was ordered to the Ministry of Justice because of his involvement in the death of the emperor's grandmother, Consort Song.

Cai's improvements to papermaking are considered to have had an enormous impact on human history. Of the people who created China's Four Great Inventions, namely the compass, gunpowder, papermaking, and printing, Cai is the only early figure whose name is known. In China he is honored in ancestor worship, deified as the god of papermaking, and appears in Chinese folklore. Outside of East Asia, however, he is mostly unknown. His hometown of Leiyang remains an active center of paper production.