Despite all of his hard work, most people remember his son Dae Joyeong as the founder of Balhae. Legacyĭae Jung-sang's forgotten establishing of a Successor-state of Goguryeo laid the foundations for the founding of an even more powerful kingdom, which was Balhae. Dae Jung-sang had another son, Dae Ya-bal (대야발), and probably also had other children besides Dae Jo-yeong because the Balhae Royal line consisted of two lineages, one from Dae Jo-yeong and the other from Dae Ya-bal. The most notable and famous of his children was his eldest, Dae Jo-yeong. Dae Jung-sang died from sickness after the battle. Geolsa died in Battle of Tianmenling, Dae Jo-yeong led the others in victorious against Li. Geolsa Biu refused the title and Wu sent general Li Kaigu to suppress the rebellions. Īccording to New Book of Tang, Wu Zetian created Dae as Duke of Jin (Zhen), Geolsa Biu as Duke of Heo (Xu), and pardon their crimes. The people of Goguryeo were subject to diplomatic power and voluntarily recognized him as their leader. The state was created by the leader of the Mohe people, who subjugated the neighboring tribes both by diplomatic and military force. Both Geolsa Biu, and Dae Jung-sang died in battle, but Dae Jo-yeong led the remaining Goguryeo and Malgal soldiers and defeated the Tang army at the Battle of Cheonmun-ryeong and established the Balhae. The two leaders resisted the Tang's attack, but were forced to retreat. Dae Jung-sang allied with the Baishan Mohe leader Geolsa Biu ( Hangul: 걸사비우, Hanja: 乞四比羽 pinyin: Qǐsì bǐyǔ), and the two powers opposed the Tang influence in 698. In 696, the Khitan led a revolt that killed the cruel governor of the protectorate and gave Yingzhou back to the Khitan. Yingzhou became part of the Tang's General Protectorate to Pacify the East, and the Khitan were enraged. Most of the Goguryeo Aristocracy, including him, were taken to Yingzhou ( Hanzi :營州), the homeland of the Khitan. The Old Book of Tang state that his eldest son, Dae Jo-yeong, was a former Goguryeo general or chief of Sumo Mohe. Though much of the credit for the founding of Balhae went to his son, many historians still give credit to Dae Jung-sang as the main supporter and leader in the founding of Balhae. Dae Jung-sang (?–698?), also known as Geolgeol Jungsang, was a key contributor to the founding of Balhae, and the father of Dae Jo-yeong, the actual founder of Balhae.