Sejong the Great

Sejong was the fourth king of the Joseon dynasty of Korea, reigning from 1418 to 1450. He is best known for creating Hangul, the Korean alphabet, but his reign also saw major advances in astronomy, timekeeping, medicine, agriculture and music, reforms of taxation and law, and the extension of Korea's northern frontier to roughly its present line. In South Korea he is widely regarded as the greatest ruler in the country's history.

Sejong was born Yi To in 1397 in Hanyang, the new Joseon capital that is now Seoul, five years after his grandfather Yi Seong-gye had overthrown the Goryeo kingdom and founded the dynasty. His father, who seized power in a struggle among the princes and reigned as King Taejong from 1400, was a ruthless consolidator of royal authority. Yi To, known as Prince Chungnyeong, was the third son and was not expected to rule; court records describe him as unusually studious, and a well-known story tells that his father once had his books taken away to protect his health.

The eldest son, Yangnyeong, was crown prince, but his conduct repeatedly embarrassed the king. In 1418 Taejong deposed him and named Chungnyeong heir, passing over the gentle second son, and two months later abdicated in his favour. The twenty-one-year-old Sejong took the throne at Gyeongbokgung Palace, though Taejong kept control of the army and remained the real power until his death in 1422.

Joseon was built on Neo-Confucian principles, and Sejong took them seriously. He attended the daily royal lectures on the Confucian classics for most of his reign, encouraged open debate among his ministers, and in 1420 expanded the Jiphyeonjeon, or Hall of Worthies, a body of young scholars who researched precedent, advised on policy and compiled books. Under him the court produced works on history, geography, ethics, law and agriculture. The Nongsa jikseol of 1429, "Straight Talk on Farming", gathered the experience of Korean farmers to suit local soils and climate rather than relying on Chinese manuals.

Land taxation was reformed after unusually broad consultation: in 1430 officials polled more than 170,000 people, from officials to peasants, on a proposed new system. The debate continued for years, and the final law of 1444 graded tax by the fertility of land and the quality of each year's harvest. Sejong also limited harsh punishments, improved conditions for prisoners, and in 1426 granted female government slaves 100 days' leave after childbirth, later extended to include a month before birth and leave for their husbands. These measures eased, but did not change, a society divided by rank in which a large part of the population was hereditarily unfree.

Sejong's reign was the high point of science in Joseon Korea. After a solar eclipse arrived later than Chinese tables predicted, he commissioned new astronomical instruments, an observatory at the palace and a calendar, the Chiljeongsan, calculated for the latitude of Seoul. Jang Yeong-sil, an engineer of humble birth whom Sejong promoted to high office, built an automatic striking water clock in 1434 and other devices, including sundials placed in public squares. In 1441 the court introduced a standardised rain gauge and sent copies to every county, creating a nationwide system of rainfall records.

Royal foundries cast improved bronze movable type for printing, building on Korean metal-type printing that dated back to Goryeo. A large medical encyclopedia, the Uibang yuchwi, and a collection of native remedies, the Hyangyak jipseongbang, were compiled. Sejong also had the court music reorganised by the scholar Bak Yeon, and is credited with composing pieces himself.

Before Hangul, Koreans wrote with Chinese characters, which were difficult to learn and poorly suited to the Korean language, so literacy was largely confined to the elite. At the end of 1443 Sejong announced a new script of twenty-eight letters, and in 1446 it was published in a text called Hunminjeongeum, "The Correct Sounds for the Instruction of the People". Its preface, attributed to the king, explains that ordinary people were unable to express themselves in writing and that the new letters were designed to be easy to learn.

The alphabet is notable for its logic: the shapes of the consonants represent the position of the tongue, lips and throat in making the sounds, and letters are grouped into syllable blocks. Historians agree that Sejong drove the project, though how much of the design was his own and how much the work of scholars of the Hall of Worthies is debated. Some senior officials, led by Choe Malli, protested that abandoning Chinese characters would lower Korea to the level of "barbarians". The script, initially disparaged as vernacular writing, remained secondary to Chinese for centuries and became the official script only in 1894.

Sejong maintained the tributary relationship with Ming China that was central to Joseon's security. In 1419, under Taejong's direction, a Korean fleet attacked the island of Tsushima, a base of the pirates who raided the Korean coast; the expedition led to a trade agreement with the island's ruling family, which controlled Japanese access to Korean ports. In the north, campaigns against the Jurchen tribes established new garrisons along the Yalu and Tumen rivers, and Sejong resettled thousands of families from the south to hold the frontier, fixing a border with China that broadly survives today.

Sejong suffered for years from poor health, including eye disease and probably diabetes, and from the 1440s gradually handed routine business to his son, the crown prince. The deaths of two sons and of his queen, Soheon, in 1444–1446 deepened his private attachment to Buddhism, which his Confucian officials resented and which contrasted with his own earlier policies restricting Buddhist monasteries. He died in 1450 and was succeeded by his son Munjong, who reigned only two years; in 1455 Sejong's second son seized the throne from the boy king Danjong, ruling as Sejo.

Sejong's achievements had lasting effect. Hangul is now the script of both Koreas and is credited with the very high literacy of modern Korea. In South Korea his statue stands in central Seoul, his portrait appears on the 10,000-won note, the administrative city of Sejong bears his name, and the anniversary of the publication of Hangul is a national holiday. North Korea also honours the alphabet, though its official histories stress the burdens Sejong's state placed on peasants. His reign is often seen as the fullest expression of the Confucian ideal of a sage king.