Geolgeol Jungsang
Dae Geol-Jungsang (Hangeul: 대걸중상; ?–698) was a Goguryo general under Yang Manchun,a Korean hero. He was the father of Dae Joyeong.
Leader of remnant Goguryo armies
After Goguryo fell to the Silla-Tang alliance armies (Korean: 나당 군 Na-Dang gun) during the year 668, Dae Geol-Jungsang and several other former Goguryo military officers rallied up the remnants of the Goguryo armies and vowed revenge on the Tang and Silla. At first, he hid this secret army when the Goguryeo prisoners of war were gathered together and sent to eight different provinces in the Tang Empire. After years of suffering under Tang oppression, General Dae reawakened the Goguryeo Remnant armies and headed back to the former territories of Goguryeo. There, he and his armies retook several of Goguryeo's fortresses and began attracting the attention of other Goguryeo people and also the attention of the Tang. Along with Dae Geol-Jungsang were the armies of the Malgal, led by Geol Sa-Biwoo. The Tang sent an army to stomp this "rebellion," and eventually caused the retreat of the Goguryeo remnant army. Geol Sa-Biwoo died during the confrontation with the Tang army and General Dae along with most of the Goguryeo remnant army retreated and went into hiding for several years.
Death
General Dae died some years after the last confrontation with the Tang. He most likely died of disease but on his death bed, appointed Dae Joyeong, his eldest, as successor and supreme commander of the Goguryeo Remnant army.
Family
The most notable and famous of his children was his eldest, Dae Joyeong. Dae Geol-Jungsang had another son, and probably also had other children besides Dae Joyeong because the Balhae Royal line consisted of two lineages, one from Dae Joyeong and the other from his brother's descendants. It is also known that he had one wife and also that he came from a middle class lineage.
Legacy
Dae Geol-Jungsang was the spark that led to the formation of the Goguryeo Remnant army, and also one of the many people responsible for founding Balhae. His son Dae Joyeong was the founder of Balhae, and his descendants as well as his brother's continued on the Balhae Royal line to the fifteenth generation. Though Balhae fell, it left a further legacy. The last princes of Balhae quickly gathered the Balhae Aristocracy and retreated to Goryeo for sanctuary. Taejo of Goryeo gladly took them in and the Dae family continued on and still survives to this day .