Yi Cheon

Yi Cheon (李蕆, 1376–1451) was a military officer, administrator, and scientist active during the reign of King Sejong of Joseon. He directed the practical work behind Sejong's scientific projects, overseeing the making of various astronomical instruments and the Gabinja metal movable type. Working alongside technicians such as Jang Yeong-sil, he played a major role in advancing the science, technology, and printing of the early Joseon period.