The Great King, Sejong () is a 2008 South Korean historical television series depicting the life of the fourth monarch of Joseon, Sejong the Great (played by Kim Sang-kyung). Considered one of the greatest kings in Korean history, Sejong created Hangul, the Korean alphabet. The series aired on KBS from January 5 to December 7, 2008 on Saturdays and Sundays at 21:30 for 86 episodes. Episodes 1 to 26 aired on KBS1, and episodes 27 to 86 aired on KBS2. Plot Born as the third son, Chungnyeong was far from ascending the throne. His early years were turbulent as Joseon faced political tensions from both within and abroad. Eventually, the young prince finds himself living in a private residence outside of the palace and experiences the everyday life of commoners until he is a young man. After his ascension to the throne, Chungyeong (now called King Sejong) stabilizes the newly born country and gives rise to a blooming culture. In the process he invents Hangul, the Korean writing system. Cast Main Kim Sang-kyung as Grand Prince Chungnyeong / King Sejong the Great Kim Do-hyun as child Grand Prince Chungnyeong Lee Hyun-woo as young Grand Prince Chungnyeong Kim Young-chul as King Taejong; Sejong's father Choi Myung-gil as Queen Wongyeong of the Yeoheung Min clan; Sejong's mother Park Sang-min as Grand Prince Yangnyeong; Sejong's first brother Jung Chan-woo as child Grand Prince Yangnyeong Lee In as teenage Grand Prince Yangnyeong Lee Jung-hyun as Royal Noble Consort Shin of the Cheongju Kim clan; Sejong's concubine Lee Yoon-ji as Queen Soheon of the Cheongsong Shim clan; Sejong's wife Nam Ji-hyun as young Lady Shim Supporting People in Joseon Royal household Lee Sang-yeob as Crown Prince Yi Hyang; Sejong's first son Oh Eun-chan as child Crown Prince Yi Hyang Kang Bit as young Crown Prince Yi Hyang Seo Joon-young as Grand Prince Suyang; Sejong's second son Choi Min-ho as young Grand Prince Suyang Yoo Seo-jin as Lady Kim, Grand Princess Consort Suseong of the Gwangsan Kim clan; Yangnyeong's wife Yeo Yoon-jung as young Lady Kim Ahn Shin-woo as Grand Prince Hyoryeong; Sejong's second brother Seo Hyun-bin as child Grand Prince Hyoryeong Yoo Tae-woong as young Grand Prince Hyoryeong Kwon Sung-hyun as Lady Jeong, Grand Princess Consort Yeseong of the Haeju Jeong clan; Hyoryeong's wife Yoon Young-joon as Prince Gyeongnyeong; Sejong's fourth brother Noh Young-hak as young Prince Gyeongnyeong Baek Seung-do as Grand Prince Seongnyeong; Sejong's