 Gim Won-sul was the second son of General Gim Yu-sin, and direct descendant of King Suro, the founder of Geumgwan Gaya.Gim Won-sul was a member of the Silla's Jinggol class, and rose to the rank of Low-level general by the time of Goguryeo's fall to the Silla-Tang Alliance.In 660, the kingdom of Baekje fell to the armies of the Silla-Tang Alliance.