Located at the former site of Seongjusa Temple, this stele was erected in memory of Nanghye, a Buddhist monk of the Unified Silla Period. Born in 801 (the 2nd year of King Aejang’s reign), he was an eighth-generation descendant of King Muyeol, and entered the monkhood at the age of 13 with the Buddhist name of Muyeom. In 821 (the 13th year of King Heondeok’s reign), he travelled to Tang China and achieved spiritual enlightenment through rigorous discipline. In 845 (the 7th year of King Munseong’s reign), he returned to Korea and became the head monk of Ohapsa Temple, which used to be located at Ungcheon (now Boryeong). As the temple came to prosper, the king gave it the name "Seongjusa”. In 888 (the 2nd year of the reign of Queen Jinseong), Muyeom passed into Nirvana at Seongjusa Temple at the age of 89, and the queen bestowed upon him the posthumous name of Nanghye.
The stele standing to the northwest of the temple site has a tortoise-shaped pedestal and a body topped with an ornamental capstone. The pedestal was seriously damaged and lay buried underground for many years, until it was discovered and repaired in 1974. The tortoise’s face is partly broken, and it has a round horn on its head, while the eyebrows are rolled into the eyes and the mouth seems to be exhaling fire. The tortoise shell features a clear double hexagonal design, with fairly thick cloud designs realistically expressed at the center. On the cloud designs, there is a square seat for resting the stele’s body, each side of which is decorated.
The inscription is carved on the facade of the stele’s long body, and both corners of the upper part of the facade are cut round. The lower part of the capstone is decorated with lotus flower carvings, while a figure of entangled clouds and a dragon are carved in relief on its upper part. The carvings on the capstone brilliantly express the energetic fiery belch of a dragon and its magnificent spirit. On the front face, the dragon’s head is, interestingly, prominent in the same direction as the tortoise head of the pedestal. The inscription, which was composed by Choe Chi-won and calligraphed by his cousin Choe In-gon, contains a detailed description of the achievements of Buddhist monk Nanghye, and also states that Nanghye’s family originally belonged to the jingol (“true bone”) class of the royal family, but slid down to the middle of the “head rank six” class in his father’s generation. As such, the inscription is a very valuable material for studies of the class system during the Silla Period. The date of the stele’s establishment is not recorded in the inscription, but since it states that the monk’s stupa was built in 890 (the 4th year of the reign of Queen Jinseong), two years after Nanghye’s death, it is presumed that the stele was erected at the same time. The stele displays the beautiful carving skills so typical of the late Silla Period, making it one of the best – as well as the largest - of those produced during that period.