In the reign of King Jinpyeong of Silla there was a man in Baekje named Jang.
His mother built a house by a pond south of the capital and lived there alone. The record says she bore the child after lying with the dragon of that pond.
The boy fed his mother by digging and selling yams. People of the country saw it and called him Seodong, the boy who digs yams.