premise: Sejong the Great died in the fifteenth century.
hypothesis: Sejong the Great ( [ se.dʑoŋ ] ; 15 May 1397 - 8 April 1450 ) was the fourth king of Joseon-dynasty Korea . During his reign from 1418 to 1450 , he governed from 1422 to 1442 and governed as regent with his son Crown Prince Munjong until his death in either 1442 or 1450 .