Sejong the Great

King Sejong reorganized the Korean government by appointing people from different social classes as civil servants. Furthermore, he performed official government events according to Confucianism, and he encouraged people to behave according to the teachings of Confucianism. As a result, Confucianism became the social norm of Korea at the time.

He suppressed Buddhism by banning outside Buddhist monks from entering Seoul and reduced the seven schools of Buddhism down to two, Seon and Gyo, drastically reducing the power and wealth of the Buddhist hierarchy.[10]

During the Goryeo dynasty, Buddhist monks wielded a strong influence in politics and the economy. With the dominant powers of the Joseon dynasty now being devout Confucianists who viewed Buddhism as a false philosophy, many officials accused the temples and monks of being corrupted by power and money. This strengthened the opposition to Buddhism within the Joseon government. One of the key factors to the suppression of Buddhism was Sejong's reform of the land system, where temple lands were seized and redistributed for development. Because of this, Buddhist temples and monks lost large amounts of economic influence and power.[11][12]

In 1427, Sejong also ordered a decree against the Huihui (Korean Muslim) community that had held special status and stipends since the Yuan dynasty. The Huihui were forced to abandon their headgear, to close down their "ceremonial hall" (mosque in the city of Kaesong) and worship like everyone else. No further mention of Muslims exist during the era of the Joseon.[13]

In the early years of the Joseon Dynasty Korea's economy was based on a barter system with cloth, grain, and cotton being the most common forms of currency. In 1423 under King Sejong’s rule the government attempted to develop a national currency modeled off of the Chinese Kaiyuan Tongbao. The Joseon Dynasty’s Joseon Tongbo was a bronze coin, backed by a silver standard, with 150 coins being equal to 600 grams of silver. Production of the Joseon Tongbo ceased in 1425 as they were expensive to produce, with the exchange rate falling to less than the intrinsic value of the coin.[14]

He collaborated closely with the Chinese Ming Dynasty. In relationship with Jurchen people, he installed 10 military posts, 4 counties and 6 garrisons (hangul: 사군육진 hanja: 四郡六鎭), in the northern part of the Korean Peninsula.

He opened three ports to trade with Japan. However, he also launched the Ōei Invasion to crush Japanese pirates (Wokou) in the East China Sea.

King Sejong was an effective military planner. He created various military regulations to strengthen the safety of his kingdom,[15] supported the advancement of Korean military technology, including cannon development. Different kinds of mortars and fire arrows were tested as well as the use of gunpowder.

In May 1419, King Sejong, under the advice and guidance of his father Taejong, embarked upon the Gihae Eastern Expedition, the ultimate goal of this military expedition to remove the nuisance of Japanese pirates who had been operating out of Tsushima Island. During the expedition, 245 Japanese were killed, and another 110 were captured in combat, while 180 Korean soldiers were killed. 146 Chinese and 8 Korean kidnapped were liberated by this expedition. In September 1419 a truce was made and the Korean army returned to Korea, but the Treaty of Gyehae was signed in 1443, in which the Daimyo of Tsushima promised to pay tribute to the King of Joseon; in return, the Joseon court rewarded the Sō clan with preferential rights regarding trade between Japan and Korea.[16]

In 1433, Sejong sent Kim Jongseo (hangul: 김종서, hanja: 金宗瑞), a prominent general, north to destroy the Jurchens (later known as the Manchus). Kim's military campaign captured several castles, pushed north, and expanded Korean territory, to the Songhua River.[17][18][19] 4 counties and 6 garrisons were established to safeguard the people from the Jurchens.

A modern reconstruction and scaled down model of Jang Yeong-sil's self-striking water clock.

In 1420 King Sejong's love for science lead him to create an institute within Gyeongbokgung palace known as the (집현전 Jade Hall) or Hall of Worthies. The institute was responsible for conducting scientific research with the purpose of advancing Korean technology. The Hall of Worthies was meant to be a collection of Korea's best and brightest thinkers, with the government offering grants and scholarships to encourage young scholars to attend.[20][21]

Sejong promoted the sciences.[22][23] He wanted to help farmers so he decided to create a farmer's handbook. The book—the Nongsa jikseol (hangul: 농사직설, hanja: 農事直說)—contained information about the different farming techniques that he told scientists to gather in different regions of Korea.[24] These techniques were needed in order to maintain the newly adopted methods of intensive, continuous cultivation in Korean agriculture.[24]

One of his close associates was the great Korean inventor Jang Yeong-sil (hangul: 장영실, hanja: 蔣英實). Jang was naturally a creative and smart thinker as a young person. Sejong noticed Jang's skill and immediately called him to his court in Seoul. Upon giving Jang a government position and funding for his inventions, officials protested, believing a person from the lower classes should not rise to power among nobles. Sejong instead believed Jang merited support because of his ability. Jang created new significant designs for water clocks, armillary spheres, and sundials.[25]

In 1442, Jang made one of the world's first standardized rain gauges named Cheugugi.[26] This model has not survived, since the oldest existing Korean rain gauge is one made in 1770, during the reign period of King Yeongjo. According to the Daily Records of the Royal Secretariat (hangul: 승정원일기；hanja: 承政院日記), King Yeongjo wanted to revive the glorious times of King Sejong the Great, and so read chronicles of Sejong's era. When he came across mention of a rain gauge, King Yeongjo ordered a reproduction. Since there is a mark of the Qing Dynasty ruler Qianlong (r. 1735–1796) of China, dated 1770,[27] this Korean-designed rain gauge is sometimes misunderstood as having been imported from China.

In 1434 Jang Yeong-sil tasked by King Sejong invented the Gabinja (갑인자, 甲寅字) printing press. The printing press was said to be twice as fast as the previous model and composed copper-zinc and lead-tin alloys.[28]

Korean celestial globe first made by the scientist Jang Yeong-Sil during the Chosŏn Dynasty under the reign of King Sejong

Sejong also wanted to reform the Korean calendar system, which was at the time based upon the longitude of the Chinese capital.[24] Sejong had his astronomers create a calendar with the Joseon capital of Seoul as the primary meridian.[24] This new system allowed Korean astronomers to accurately predict the timing of solar and lunar eclipses.[24][29]

In the realm of traditional Korean medicine, two important treatises were written during his reign. These were the Hyangyak jipseongbang and the Euibang yuchwi, which historian Kim Yongsik says represents "Koreans' efforts to develop their own system of medical knowledge, distinct from that of China."[24]

In 1426, Sejong the Great enacted a law that granted government nobi women 100 days of maternity leave after childbirth, which, in 1430, was lengthened by one month before childbirth. In 1434, Sejong also granted the husbands 30 days of paternity leave.[30]

In order to provide equality and fairness in taxation for the common people, Sejong the Great issued a royal decree to administer a nationwide public opinion poll regarding a new tax system called Gongbeop in 1430. Over the course of 5 months, the poll surveyed 172,806 people, of which approximately 57% responded with approval for the proposed reform.[31][32]

Sejong depended on the agricultural produce of Joseon's farmers, so he allowed them to pay more or less tax according to fluctuations of economic prosperity or hard times. Because of this, farmers could worry less about tax quotas and work instead at surviving and selling their crops. Once the palace had a significant surplus of food, King Sejong then distributed food to poor peasants or farmers who needed it.

In 1429 Nongsa-jikseol (hangul: 농사직설, hanja: 農事直說, "Explanations of Agriculture") was compiled. It was the first book about Korean farming, dealing with agricultural subjects such as planting, harvesting, and soil treatment.

Sejong was also a writer. He composed the famous Yongbi Eocheon Ga ("Songs of Flying Dragons", 1445), Seokbo Sangjeol ("Episodes from the Life of Buddha", July 1447), Worin Cheon-gang Jigok ("Songs of the Moon Shining on a Thousand Rivers", July 1447), and the reference Dongguk Jeong-un ("Dictionary of Proper Sino-Korean Pronunciation", September 1447).

One of Sejong’s closest friends and mentors was the 15th century Korean musician Bak Yeon. Together they composed over two hundred musical arrangements. Sejong’s independent musical compositions include the Chongdaeop (Great Achievements), Potaepyong (Preservation of Peace), Pongraeui (Phoenix), and Yominrak (A Joy to Share with the People). Yominrak continues to be a standard piece played by modern traditional Korean orchestras, while Chongdaeop and Potaepyong are played at memorial ceremonies honoring the Kings of the Joseon Dynasty today.[33]

In 1418 under the reign of King Sejong, Koreanscholars developed the (편경 編磬) Pyeongyeong, a lithophone modeled off of the Chinese Bianqing. The Pyeongyeong is a percussion instrument consisting of two rows of 8 pumice slabs hung on a decorative wooden frame with a 16-tone range and struck with an Ox Horn mallet. The Pyeongyeong was manufactured using pumice mined from the Kyonggi Province and used primarily for ceremonial rights.[34][35]

Hunmin Jeongeum Eonhae

King Sejong the Great profoundly affected Korean history with his personal creation and introduction of hangul, the native phonetic writing system for the Korean language.[4][36] Although it is widely assumed that King Sejong ordered the Hall of Worthies to invent Hangul, contemporary records such as the Veritable Records of King Sejong and Jeong Inji's preface to the Hunminjeongeum Haerye emphasize that he invented it himself.[37]

Before the creation of Hangul, people in Korea (known as Joseon at the time) primarily wrote using Classical Chinese alongside phonetic writing systems based on Chinese script that predated Hangul by hundreds of years, including idu, hyangchal, gugyeol, and gakpil.[38][39][40][41] However, due to the fundamental differences between the Korean and Chinese languages,[42] and the large number of characters that needed to be learned, there was much difficulty in learning how to write using Chinese characters for the lower classes, who often lacked the privilege of education. To assuage this problem, King Sejong created the unique alphabet known as Hangul to promote literacy among the common people.[43] His intention was to establish a cultural identity for Korea through its unique script.

• King Sejong created the Korean alphabet (which numbered 28 letters at its introduction, of which four letters have become obsolete), with the explicit goal being that Koreans from all classes would read and write. Each consonant letter is based on a simplified diagram of the patterns made by the human speech organs (the mouth, tongue and teeth) when producing the sound related to the character, while vowels were formed by combinations of dots and lines representing heaven (a circular dot), earth (a horizontal line) and humanity (a vertical line). Morphemes are built by writing the characters in syllabic blocks. The blocks of letters are then strung together linearly.

Hangul was completed in 1443 and published in 1446 along with a 33-page manual titled Hunmin Jeong-eum, explaining what the letters are as well as the philosophical theories and motives behind them.[44] The Hunmin Jeong-eum purported that anyone could learn Hangul in a matter of days. People previously unfamiliar with Hangul can typically pronounce Korean script accurately after only a few hours of study.

King Sejong faced backlash from the noble class as many disapproved of the idea of a common language, with some openly opposing its creation. Many within the noble class believed that giving the peasants the ability to read and write would allow them to find and abuse loopholes within the law. Others felt that Hangul would threaten their families’ positions in court by creating a larger pool of civil servants. The Korean elite continued to use Chinese Hanja long after Sejong’s death in 1450.[45] Hangul was often treated with contempt by those in power and received criticism in the form of nicknames, including Eonmun (meaning Vulgar Script), Amkeul (meaning Woman’s Script), and Ahaekkeul (meaning Children’s Script).

Despite this, Hangul gained popularity among women and fiction writers. In 1504 the study and publication of Hangul was banned by King Yeonsangun.[46] The spread and preservation of Hangul can be largely attributed to three main factors, books published for women, its use by Buddhist monks,[47] and the introduction of Christianity in Korea in 1602.[48] Hangul was brought into the mainstream of Korean culture in the 16th century, due to a renaissance in Korean literature and poetry. Hangul continued to gain popularity well into the 17th century, and gained wider use after a period of Korean Nationalism in the 19th century. In 1849 Hangul was adopted as Korea’s national writing system, and saw its first use in official government documents. After the annexation of Korea by Japanese forces Hangul was outlawed again until the liberation of Korea in 1945.[49][50]

A 9.5-meter-high (31 ft) bronze statue of King Sejong was placed in 2009 on a concrete pedestal on the boulevard of Gwanghwamun Square and directly in front of the Sejong Center for the Performing Arts in Seoul.[65] The sculptor was Kim Young-won.[66] The pedestal contains one of several entrances to the 3,200 square meter, underground museum exhibit entitled "The Story of King Sejong".[67][68] It was dedicated on Hangul Day in celebration of the 563rd anniversary of the invention of the Korean alphabet by King Sejong.[69]

The street Sejongno and the Sejong Centre for the Performing Arts, both located in central Seoul, are named after King Sejong.[70]

In early 2007, the Republic of Korea government decided to create a special administrative district from part of the present South Chungcheong Province, near what is presently Daejeon. The district was named Sejong Special Autonomous City.

King Sejong the Great, as depicted on the Bank of Korea's 10,000 won banknote (Series VI).

A portrait of Sejong is featured on the 10,000 won banknote of the South Korean won, along with various scientific tools invented under his reign.

The life of Sejong was depicted in the KBS Korean historical drama King Sejong the Great in 2008.[71] Sejong is also depicted in the 2011 SBS drama Deep Rooted Tree and 2016 KBS1 drama Jang Yeong-sil.

• Portrayed by Han In-soo in the 1983 MBC TV series 500 Years of Joseon Dynasty: Tree with deep roots.
• Portrayed by Song Jae-ho in the 1998–2000 KBS TV series King and Queen.
• Portrayed by Kim Sang-kyung in the 2008 KBS2 TV series King Sejong the Great and in the 2016 KBS1 TV series Jang Yeong-sil.
• Portrayed by Lee Hyun-woo in the 2008 KBS2 TV series King Sejong the Great.
• Portrayed by Ahn Sung-ki in the 2008 film The Divine Weapon.
• Portrayed by Jeon Moo-song in the 2011 JTBC TV series Insu, The Queen Mother.
• Portrayed by Han Suk-kyu, Song Joong-ki and Kang San in the 2011 SBS TV series Deep Rooted Tree.
• Portrayed by Ju Ji-hoon in the 2012 film I Am the King.
• Portrayed by Yoon Doo-joon in the 2015 MBC TV series Splash Splash Love.
• Portrayed by Nam Da-reum in the 2015 SBS TV series Six Flying Dragons.
• Portrayed by Han Suk-kyu in the 2019 film Forbidden Dream.
• Portrayed by Song Kang-ho in the 2019 film The King's Letters.
• Portrayed by Jang Dong-yoon in the 2021 SBS TV series Joseon Exorcist.
• Portrayed by Kim Min-ki in the 2021–2022 KBS1 TV Series The King of Tears, Lee Bang-won.

• Leader of the Korean civilization in Sid Meier's Civilization V.
• Leader of the Korean civilization in Civilization Revolution 2.
• King Sejong Station LE, a major tournament map in the game StarCraft II: Heart of the Swarm.
• Starting ruler of Korea in Europa Universalis IV.