King Seondeok of Silla (?–785), personal name Kim Yang-sang, was the 37th ruler of Silla and the 8th ruler of Unified Silla. Prior to that, he served as a Sangdaedeung to King Hyegong of Silla.
His birth name was Kim Yang-sang. He was an eleventh-generation descendant of King Naemul, and the Daughter of haechan Kim Hyo-bang by King Seongdeok's daughter Lady Saso. He married Lady Gujok, the daughter of gakgan Kim Yang-pum. Seondeok served under King Hyegong in the position of sangdaedeung.
In 780, ichan Kim ji-Jeong, led a rebellion against King Hyegong. The King ordered the then Sangdaedeung Kim Yang-Sang(later, King Seondeok) to fight off the rebels. However, the rebel forces succeeded in storming the palace and killed King Hyegong and his Queen. Kim Yang-san was then proclaimed as Silla's new ruler. Some historians believed that King Seondeok may have killed King Hyegong himself, since he was the one who benefited the most from his death.
After his death in 785, Seondeok was cremated and his ashes scattered on the Sea of Japan (East Sea). Seondeok's successor was King Wonseong.[1]