The legend of Munmuwang tells the story of Silla’s 30th monarch King Munmu, eldest son of King Muyeol, who completed the unification of the Three Kingdoms. The narrative weaves together King Munmu’s last words that in death he would become a dragon to protect the kingdom, and historical sites and relics including Gameun Temple, Daewang Hermitage, Igyeon Pavilion and Manpasikjeok (Pipe That Calms Ten Thousand Billows). The dragon in this legend is later combined with the dragon of Korean folklore, related to wealth, and the dragon as state protector.
As he lay dying, King Munmu left a will that he be buried on a huge rock in the middle of Dongahe (East Sea). While alive, the king had repeatedly said to Monk Jieui, “When I die, I shall turn into a huge dragon and uphold Buddhism as guardian of the state.” The monk would respond, “Would it be acceptable for Your Majesty to be reborn as a beast to become a dragon?” to which the king answered, “I have long nurtured a resentment for worldly glories. If I am reborn into the terrible fate of a beast, it would suit my wishes perfectly.” His son King Sinmun, who inherited the throne, built Gameun Temple on the shore of the East Sea for his deceased father. According to temple records, King Munmu began construction of the temple in defense against the invading Japanese troops but died before completion and became a dragon. His son King Sinmun completed the interior of the temple in in the 2nd year of Kaiyao under the reign of Gao Zong of Tang China (682). A hole was made under the temple’s threshold toward the east, to prepare for the day when the dragon would enter the temple and take up residence. The deceased king’s will called for his bones to be kept on an islet to serve as his tomb, naming it Daewangam (Great King Rock); for the temple to be named Gameunsa; and the pavilion where the king reappeared as a dragon to be named Igyeondae.
In Korean culture, the dragon came to be perceived as a state protector, a concept that combined dragon worship in folk religion and the dragon as protector of Buddhism. The legend of King Munmu carries on the state protector dragon narrative but is distinctive in that the king proclaims himself as the state protector dragon, a uniquely Korean motif.