Sejong the Great
Before the creation of Hangul, people in Korea (known as Joseon at the time) primarily wrote using Classical Chinese alongside phonetic writing systems based on Chinese script that predated Hangul by hundreds of years, including idu, hyangchal, gugyeol, and gakpil. However, due to the fundamental differences between the Korean and Chinese languages, and the large number of characters that needed to be learned, there was much difficulty in learning how to write using Chinese characters for the lower classes, who often lacked the privilege of education. To assuage this problem, King Sejong created the unique alphabet known as Hangul to promote literacy among the common people. His intention was to establish a cultural identity for Korea through its unique script.
Hall of Worthies
The Hall participated in various scholarly endeavors, of which the best-known may be the compilation of the "Hunminjeongeum", in which the hangul writing system was first formulated. In the Hunminjeongeum, King Sejong wrote a preface which explained the origin and purpose of the newly created alphabet, Hangul. He then instructed his scholars of the Jiphyeonjeon (Hall of Worthies) to write detailed explanations of each of its letters along with examples of each of them. The purpose of the Hunminjeongeum was to provide instructions on how to use the new alphabet. The definitive edition of the Hunminjeongeum is known as the Haerye Edition of Hunminjeongeum (Haerye refers to the explanations and examples of the Hall of Worthies scholars, which were previously missing in other known editions)