Who is traditionally credited with developing Hangul?

The development of Hangul, the phonetic writing system for the Korean language, is traditionally credited to Sejong, the fourth king of the Joseon (Yi) dynasty.123

King Sejong developed the system in 1443 with the specific goal of improving literacy among the Korean people. It was officially promulgated in 1446 under the name Hunminjeongeum, which translates to "Proper Sounds to Instruct the People". While the script is a remarkable featural system that functions independently of Chinese orthography, it was not widely adopted by the elite class for several centuries due to the prevailing influence of Confucianism and Chinese culture.124