Ancient, Ruined and Relatively Obscure Temple in Gokseong-gun County, South Jeolla Province one of the "Great 108" Korean temples
Seongdeok-san Gwaneum-sa [Saint-Virtue Mountain Bodhisattva of Compassion Temple] is located in Seonsei-ri Village, Osan-myeon District, Gokseong-gun County of Jeolla-namdo Province. It is purported to have founded around 300 CE during the reign of the Baekje Kingdom's King Bunseo. If this is true, then it's one of Korea's oldest Buddhist temples; but it cannot be verified -- Baekje is known to have adopted Buddhism in 384 CE.
It is said that a missionary-monk from China named Seongdeok (in Korean; this could be a generic name "virtuous saint") brought a golden of Gwanse-eum-bosal the Bodhisattva of Compassion [Geumdong Guanyin Bosal Sang] from "Naganan-po" (a port) to this place (presumably after presenting it to the king), enshrined it here in a round-shaped hall called the Wontong-jeon [圓通 殿, Circular Pass-through Hall, a shrine for circumambulating a holy icon], and started a temple named Gwaneum-sa; later the mountain became named after him.
We have no records of this monastery from the Three Kingdoms, Unified Shilla and Early Goryeo eras (5th~13th centuries). King Gongmin, the last important ruler of the Goryeo Dynasty, ordered and financed major renovations and expansion of it in 1374, according to dynastic records. Experts say that the historic Wontong-jeon displayed characteristics of late-Goryeo hanok architecture. It was badly damaged by Japanese invaders during the 1592-98 Imjin War in the middle of the Joseon Dynasty, and then reconstructed starting in 1604.
In modern times, Master Yeongdam repaired this temple in 1912 after it had suffered a fire, but it was all burned down again during the 1950-53 Korean War -- and at that time, the historic Wontong-jeon and its precious Geumdong Guanyin Bosal Sang were lost. The 13 buildings that are now there are newly constructed since the 1970s, and it was designated as Jeollanam-do's 24th Cultural Heritage Site in 1984; it is not designated as a national site due to its lack of remaining physical history, but is still regarded as significant enough to be on the list of Korea's Great-108 Temples.