China is an ancient civilization, since ancient times has a splendid culture and brilliant achievements of civilization, for a long time, our scientific and technological level is ahead of the world. When it comes to China's ancient scientific achievements, then the "four major inventions" must be an unavoidable topic.
The four great inventions come from the British sinologist Joseph Ejør, who believes that papermaking, compass, gunpowder and printing are the four most representative inventions in ancient China and the most influential on the development of world civilization.

Among the four major inventions, papermaking optimized the carrier of writing, which is more conducive to the preservation and transmission of ideas; the compass guided people in the direction and became an important tool for people to find a way in the age of great navigation; gunpowder had great power and was widely used in many fields in the future; printing facilitated the efficiency of putting words into paper and accelerated the spread of ideas. In general, they are all very good inventions, and the contribution of papermaking is far-reaching and lasting.
When it comes to papermaking, it is impossible not to mention its reformer, the famous eunuch Cai Lun, who some people say is proficient in his skills as a eunuch, but there are also views that others are inferior in character, and even the motivation for improving papermaking is very impure.
So, let's take a look at what Cai Lun really is like.
In the middle of the Eastern Han Dynasty, Cai Lun was born in Guiyang County, which is in the area of present-day Chenzhou, Hunan. In the western part of Guiyang County, there is a "Ōmiyama Mountain", where silver ore is abundant, so the smelting industry is very developed, and the surrounding business travel is frequent, which is also quite prosperous. Because of the prosperity of the smelting industry, there were many blacksmiths living under the Mountains, and Cai Lun was born in one of the families that had been engaged in iron smelting for generations. Influenced by her family, Cai Lun has been learning knowledge and craftsmanship since she was a child, and she is relatively familiar with common production methods.
It is said that Cai Lun's family had a good relationship with local officials because of iron smelting affairs, and under the recommendation of officials, the young Cai Lun was sent to the palace. From today's point of view, it is a great shame to be a eunuch who represents the need to cut off children and grandchildren, but in ancient times, entering the palace represented the opportunity to serve the emperor, not only to eat and wear no longer worry, but also to enjoy the high-ranking official Houlu. In the feudal society divided by the rank of scholars, farmers, industrialists and merchants, cai lun's family was not very high as a family of craftsmen, and it was necessary to work hard to exchange food for food, and after some deliberation, Cai Lun was sent to the imperial palace by his parents.
Because of the inconvenience of transportation conditions in the past, most of the eunuchs in the palace were taken from the nearest materials to find suitable candidates from the children near the capital, so according to the current historical data, Cai Lun from Guiyang may be the first eunuch from the south in China's history. When Cai Lun first entered the palace in the last year of The Han Ming Emperor Yongping, he was arranged to work as an errand boy in the "Ye Court" where the concubines lived, responsible for some chores. After Emperor Zhang of Han succeeded to the throne, with the accumulation of seniority and diligent work, Cai Lun was enthroned as a small yellow gate, and his function changed to entering and leaving miyagi to convey some of the emperor's edicts.
Because of his education and cleverness, Cai Lun gradually gained reuse and his talent slowly unfolded. Emperor Han Zhang died after thirteen years on the throne, and Emperor Han and Emperor succeeded to the throne, at this time, Cai Lun was already an "old man" in the palace and was very much respected by everyone.
Emperor He was young at the time, but Empress Dowager Dou was once served by Cai Lun, and Cai Lun was thus given the title of Zhongchang Attendant and began to have a say in the affairs of the imperial court. In the ninth year of Yongyuan (97), because he was born in a family of craftsmen, Cai Lun was entrusted with the production of instruments in the palace, and under the supervision of insiders, the artifacts in the palace were improved in quality.
However, as the work slowly deepened, Cai Lun found that the papermaking technique of the past had great flaws. According to the Book of the Later Han Dynasty, "Since ancient times, the book qi has been compiled in bamboo jane, and its use of silk is called paper. Expensive and simple, it is not convenient for people. That is to say, since ancient times, most of the people record the text using bamboo Jane, because bamboo Jane is too bulky, so some people take silk cloth to write, call it "paper", although the silk cloth is light and thin, but the price is too expensive, bamboo Jane cost is low but too heavy, there are great problems.
In this case, Cai Lun "uses tree skin, hemp head, cloth and fishing nets as paper", which greatly reduces the cost of paper, and because of the advanced technology, the quality of the new paper produced is also very good. In the first year of the Yuan Dynasty (105), Cai Lun dedicated the improved paper and technology to the Han and Emperor He, who immediately ordered the promotion of this skill. In order to express his gratitude to Cai Lun, his descendants called his modified paper "Cai Hou Paper" according to his title of "Marquis of Longting".
Cai Lun's glory and wealth in the palace continued until the first year of Jianguang (121), the year in which Emperor An of Han was pro-government, and his grandmother Song Guiren was persecuted to death by Cai Lun. Since Cai Lun was an old courtier in the palace and had previously been instructed by Empress Dowager Dou, Emperor An of Han ordered him to go to the court to be tried himself. However, at this time, the elderly Cai Lun did not want to accept the trial, so he chose to take poison and commit suicide.
For Cai Lun, Fan Ye, author of the Book of the Later Han Dynasty, commented: "Lun has the talent to learn, dedication and prudence, several offenses are strict, and Kuang Bi gains and losses. It can be said that in general, he was a relatively loyal and virtuous courtier, and although he had committed crimes against his concubines, his achievements in improving papermaking were more worthy of attention by future generations. Yes
People say that Cai Lun's character is poor, but in the history books, he did not commit any crimes that harmed the country and the people, perhaps he was directly advised and improved papermaking techniques just to be more favored, but after being promoted to the rank of knight, he did not deceive the king like the future Ten Permanent Attendants, which is commendable.