Sejong the Great

Oversaw the creation of Hunminjeongeum and promoted scholarship, science and technology; the most revered monarch of the Joseon dynasty.

Life

Accession by abdication

Sejong, personal name Yi Do, was the third son of Taejong (Yi Bang-won). In 1418 Taejong deposed his eldest son, Grand Prince Yangnyeong, named Sejong crown prince instead, and abdicated that same year; Sejong took the throne at 21, while Taejong, as retired king, kept control of the military until his death in 1422. Studious from childhood, Sejong expanded the Jiphyeonjeon (Hall of Worthies) after his accession, selecting young scholar-officials to devote themselves to studying institutions, the classics and history; many important works came from the hands of these scholars.

Civil rule and science

Under Sejong, Joseon achieved much in many fields: works such as Nongsa jikseol (Straight Talk on Farming) and Hyangyak jipseongbang (Compendium of Native Korean Prescriptions) were compiled; Jang Yeong-sil and others were commissioned to build rain gauges, the Angbu ilgu hemispherical sundial and the Jagyeongnu (a self-striking water clock); and the calendar Chiljeongsan was revised. In 1419 he sent troops against Tsushima Island to strike at the bases of the wokou (Japanese pirates), and in the north he established the Four Commanderies and Six Garrisons along the Yalu and Tumen rivers, largely fixing Korea's northern border.

Created Hunminjeongeum

In 1443 Sejong and the scholars of the Hall of Worthies created an alphabet of 28 letters, promulgated in 1446 under the name Hunminjeongeum; its preface explains that the script was made so that common people who could not read Chinese characters could also express themselves. The new script met opposition from some scholar-officials, but Sejong insisted on promoting it. In his later years he suffered from eye disease, diabetes and other ailments, and he died in 1450. Today his portrait appears on South Korea's 10,000-won banknote.

Legacy

Sejong is regarded in South Korea as one of the greatest monarchs and is honored with the title "the Great." The Hunminjeongeum whose creation he directed is the forerunner of today's Korean alphabet and one of the few scripts in the world whose creator and purpose are known with certainty. His era was rich in scientific instruments, agricultural treatises and medical works. Under the Joseon, however, the scholar-official class long dismissed Hunminjeongeum as "eonmun" (vernacular script), and official documents continued to be written mainly in Classical Chinese; only in modern times did it become the script in general use.

Major works & achievements

• Created Hunminjeongeum in 1443 and promulgated it in 1446
• Expanded the Jiphyeonjeon and compiled works such as Straight Talk on Farming
• Oversaw the making of instruments such as rain gauges and the self-striking water clock
• Established the Four Commanderies and Six Garrisons, fixing the northern border

Did you know? The Haerye edition of the Hunminjeongeum was inscribed on UNESCO's Memory of the World Register in 1997.

Key dates

• 1418Accession by abdication
• 1419Sent troops against Tsushima Island
• 1420Expanded the Jiphyeonjeon
• 1441Built rain gauges
• 1443Created Hunminjeongeum
• 1446Promulgated the Hunminjeongeum
• 1450Died