Sejong the Great

Would you rather have a leader who is powerful or one who is wise? Can wisdom lead to strength? Is it better to break with tradition, to follow it, or to adapt it to suit your circumstances?
This lesson was reported from:
Adapted in part from open sources.

South Korean 10000 Won note featuring King Sejong.
South Korean 10000 won note featuring King Sejong.

A Tradition of Intellectuals

Due in large part to its Confucian tradition, Korea is a nation that honors intellectuals and scholars above warriors and conquers.  Just look at the faces that decorate Korean currency – these are some of the most accomplished philosophers, poets, calligraphers, and thinkers from the country’s 2000 year history.  Only one – Admiral Yi on the 100 won coin – could be considered a warrior, and he is most celebrated for his originality and innovation rather than for his ferocity.  Each of these figures has a biography full of travel, adventure, insight, and influence, but King Sejong the Great (reigning from 1418 to 1450) stands as the most preeminent and renowned of the Korean scholar heroes.  There he is on the 10000 won note.

Merit over Tradition

Sejong was born on May 15, 1397, the third son of King Taejong. As a young prince, Sejong excelled in various studies and was favored by King Taejong over his two older brothers.

Royal procession of King Sejong the Great.
Royal procession of King Sejong the Great.

Taejong’s eldest son, Yangnyeong, was named heir apparent in 1404. However, Yangnyeong’s free spirited nature as well as his preference for hunting and leisure activities resulted in Yangnyeong being removed from the position of heir apparent in June of 1418.   The government was purged of those officials who disagreed with the removal of Yangnyeong. In August of 1418, Sejong became the fourth king in Korea’s Joseon Dynasty, one of the longest lasting and most stable dynasties in world history.

King Sejong.

As the third son of Taejong, Sejong’s ascension to the throne was unique.  He rose on his own merit, not his birthright – a concept that he would apply broadly to social policy, scholarly research, and civil service throughout his reign.

Timeline of Key Events in the Life and Reign of Sejong

  • 1397- Sejong is born as the 3rd son in the 4th generation of the Joseon Dynasty to Queen Wonkyong and King Taejong.
  • 1409- Sejong is officially named a prince.
  • 1413- Prince Sejong assumes the title of Grand Prince.
  • 1418- Prince Sejong is inaugurated as Crown Prince in place of his older brother, Yangnyong.
  • 1418- Prince Sejong assumes the throne as the 4th king of the Joseon dynasty.
  • 1420- King Sejong founds the Jiphyeonjeon (Hall of Worthies), also known as the Jade Hall, a royal research institute next to his palace in modern day Seoul.
  • 1443- Sejong develops hangul (the great writing), the new Korean alphabet.
  • 1446- Hangul becomes the official language of Joseon Korea.
  • 1450- Sejong the Great dies and his son, Prince Munjong, succeeds him as the 5th king of the Joseon Dynasty.
 Jiphyeonjeon (Hall of Worthies), also known as the Jade Hall, a royal research institute next to his palace in modern day Seoul.
Jiphyeonjeon (Hall of Worthies), also known as the Jade Hall, a royal research institute next to Sejong’s palace. (Seoul, South Korea, 2015.)

Achievements of King Sejong

Merit-Based Politics

Confucian Scholar and Pupils, Joseon Korea.
Confucian Scholar and Pupils, Joseon Korea.

Traditionally, only the Yangban (aristocrats) served in government posts.  King Sejong revolutionized government by appointing people from different social classes as civil servants based on their merit, measured through a civil service exam modeled on the Chinese example. 

The exams did not cover knowledge of the civil or criminal laws of the empire, diplomatic strategy, tax code, or any other immediately practical topics.  Instead, they focused on how well a candidate could quote and discuss the Confucian classics – ancient texts that outlined the ethics and ideas of Chinese philosopher Confucius (551–479 BCE).  Confucianism focuses on the social and political order that comes from a proper respect for the importance of honoring the family (also called filial piety) and social harmony.

Confucius, the great Chinese philosopher.

According to Confucius, each person had a specific place in society and certain duties to fulfill. Confucius hoped that if people knew what was expected of them they would behave correctly. Therefore, he set up five principal relationships in which most people are involved. These relationships were (1) ruler and subject; (2) father and son; (3) elder brother and younger brother; (4) husband and wife; and (5) friend and friend. 

Confucius placed great importance on the family. Family fife was seen as a training ground for life in society. It is at home in the family that the child learns to deal with problems that he or she will face later in the world. The family is responsible for educating the child to be a good member of society. Confucius emphasized the importance of education, the aim of which is to turn people into good family members, responsible members of society, and good subjects of the king.

The state (government) was regarded as an extension of the family in many ways. The king and his officials were referred to as the parents of the people. Subjects owed the same loyalty to their rulers that they owed to the senior members of their family.

The Chinese Model

All of this was modeled on the Chinese system, held by many Koreans due to their wealth, military power, and complex culture to obviously be the most civilized nation in the world.  As a result of Sejong’s innovations, Confucianism became and continues to be the social norm in Korea to this day.

Science and Technology

King Sejong had great respect for scholarship and believed that one of the most important functions of education and research was to improve the lives of others.  He once wrote, “Unlike many other occupations, scholars have the greatest responsibility to the people. Their work can ultimately improve the lives of all people for many decades. But if an academic becomes lost in his study, he cannot see how his work can benefit others. Therefore, like a well-balanced fencing stance, or a reasonable argument, the scholar’s life must be even and balanced.” 

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

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 was compiled under the supervision of King Sejong. It was the first book about Korean farming, dealing with agricultural subjects such as planting, harvesting, and soil treatment.

King Sejong the Great is revered by Koreans for his outstanding policies reflecting his devotion to service to the nation rather than his own glory. His welfare policies compare favorably with those in the 21st century. He gave slaves and spouses 100 days off for maternity leave.  

An armillary sphere for modeling celestial motion, developed under King Sejong.
An armillary sphere for modeling celestial motion, developed under King Sejong. (Seoul, South Korea, 2015.)

He also promoted Jang Yeong-sil, a peasant, to a high-ranking palace position because he was an extremely talented inventor-scientist.  As a child, Jang was naturally creative and observant. However, Jang was at the bottom of the social order. Upon Jang’s promotion, many palace 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 significant new designs for water clocks, armillary spheres, and sundials.  However, his most impressive invention came in 1442 when he invented the world’s first rain gauge named the Cheugugi.


In 1420, King Sejong established the Jiphyeonjeon (Hall of Worthies), also known as the Jade Hall, a royal research institute next to his palace in modern day Seoul.  He gathered the foremost scholars and writers of the time and had them compile some 20 works on history, geography, astronomy, mathematics, military science, pharmacology, and agriculture. These also included encyclopedias on Chinese medicine and Korean medicine (hanyak). In cooperation with the best scholars of his day, Sejong created the modern written alphabet for the Korean language.

Before the creation of Hangul, only members of the highest class, the hereditary Yangban, were literate – important documents were written in Classical Chinese, which features tens of thousands of characters and is a completely different language from Korean.  For day to day writing, Chinese characters would be used to represent Korean words – but this was challenging, too.  Just imagine using Chinese characters to write English – it’s enough to make your head hurt.  While creating the alphabet, King Sejong encountered opposition of conservative Yangban who argued for the tradition and beauty of Chinese.  On the other hand, the lower classes could not express themselves in writing, could not study the classics…  For a scholar king, this was intolerable.

King Sejong presided over the introduction of the 28-letter Korean alphabet in 1446, with the explicit goal being that Koreans from all classes would read and write. People previously unfamiliar with Hangul can typically pronounce Korean script accurately after only a few hours of study. Sejong’s intention was to establish a cultural identity for Korea through its unique script.  

Each hangul letter is based on a simplified diagram of the patterns made by the mouth, tongue and teeth when making the sound related to the character.  Instead of being written sequentially like the letters of the Latin alphabet, Hangul letters are grouped into blocks, such as 한 han, each of which transcribes a syllable. That is, although the syllable 한 han may look like a single character, it is actually composed of three letters: ㅎ h, ㅏ a, and ㄴ n. Each syllabic block consists of two to six letters, including at least one consonant and one vowel. These blocks are then arranged horizontally from left to right or vertically from top to bottom. Each Korean word consists of one or more syllables, hence one or more blocks.  

Death and Legacy

Sejong was blinded years later by diabetes complications that eventually took his life in 1450. He was buried at the Yeong Mausoleum. His successor was his first son, Munjong. Sejong judged that his sickly son, Munjong, was unlikely to live long and on his deathbed asked the Hall of Worthies scholars to look after his young grandson, Danjong. As predicted, Munjong died two years after his accession, and political stability enjoyed under Sejong disintegrated when Danjong became the sixth king of Joseon at the age of twelve. 

Sejong is one of only two Korean rulers posthumously honored with the appellation “the Great.”  He is the star of TV shows, video games, and is honored among other places, with statues and street names. 

King Sejong statue in downtown Seoul.
King Sejong remains a foundational figure, even as South Korea has modernized and democratized in the 21st century. (Seoul, South Korea, 2015.)
“If the people prosper, how can the king not prosper with them? And if the people do not prosper, how may the king prosper without them?”  -King Sejong, 4th Ruler of Joseon Korea

 The Bottom Line

  1. Sejong once wrote, “All that I am, or will be, I have learned from my family, my friends, my teachers…” How are his Confucian virtues revealed in this statement?  Why do Koreans consider Sejong to be one of their great national heroes?
  2. The Chinese word for China is Zhōngguó, which can be translated as “the Middle Kingdom” – meaning that it is the center of the universe.  It was considered by many neighbors to be the height of civilization and stood in contrast with barbarians such as Mongols to the north.  In what ways do you see Korea’s great leader Sejong imitating China, and in what ways do you see him distinguishing Korean culture from Chinese?  Is it better for a nation to adopt a dominant neighbor’s ways, or to create its own distinct culture?
  3. Why is Hangul so important a tool in Sejong’s plan to create a meritocracy, and in the long term, an important democratizing tool?
  4. What qualities make a leader great?  Who is one of the greatest heroes of your nation?  In what lasting ways have they shaped your life?
  5. Research and evaluate the achievements and qualities of one of the historical figures featured on the other denominations of South Korean won listed below.  What does his or her inclusion on the national currency say about Korean values and aspirations?
₩1000 – Yi Hwang
₩5000 – Yi I
₩10 000 – Sejong the Great
₩50 000 – Shin Saimdang


Gyeongbokgung Palace. (Seoul, South Korea, 2015.)

You can actually visit parts of the world featured in this lesson:

A Guided Tour of South Korea is a curated photo essay for use in middle and high school social studies classrooms.  The essay offers a brief, completely non-comprehensive overview of South Korean historical and cultural sites circa 2015 and is meant to present these and related topics in an unconventional way – that is, as if the student were travelling through, wandering, and exploring South Korea on their own.  From the glistening towers of Seoul to the DMZ, from the bustle of downtown to the sanctuary of its Buddhist monasteries – supplementary photos to enhance a sense of place.