The fifteenth century is remembered as an age of peace and prosperity under King Sejong's rule. His contributions to Korean society were many during his 32 year rule. He compelled the production of a sundial, a water meter, a rain-gauge, planetariums, a celestial globe, and astronomical maps.
In 1420, King Sejong established the Chipyon chon (Hall of Worthies), a royal research institute. 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, as well as encyclopedias on Chinese medicine and Korean medicine (hanyak). The collection also includes some of King Sejong's own poems praising Buddha entitled Worin Chon-gangjigok.
King Sejong governed his people with affection and virtue. He was willing to see his own mistakes and was quick to point out other's integrity, thus endearing him to his friends and subjects alike. King Sejong's strength of character and remarkable intellect were combined with genuine humility. In his journal, he wrote:
"All that I am, or will be, I have learned from my family, my friends, my teachers, and training with the sword."