Onjo- Korean HeroHero"Founder of Baekje"
Also known as: 온조 and 溫祚
Titles & Epithets
Domains
Description
Leading his mother's followers southward from Goguryeo, a young prince plants his banner at Wiryeseong and raises the walls of a new kingdom. When his brother Biryu's coastal settlement crumbles, Biryu's people turn to Onjo, and Baekje stands whole.
Mythology & Lore
The Southward Migration
According to the Samguk Sagi, Onjo was the younger of two sons born to Jumong, founder of Goguryeo, and Soseono, a woman of considerable wealth and political influence. When Yuri, Jumong's firstborn son from a previous union, arrived in Goguryeo and was named heir, Soseono recognized that her own sons had no future at court. She gathered her followers and resources and led Onjo and his elder brother Biryu south in search of new lands.
The brothers disagreed about where to settle. Biryu chose the coastal area of Michuhol, believing the sea would provide for his people. Onjo, counseled by ten ministers who had accompanied the migration, selected the fertile inland site of Wiryeseong along the Han River. He established his kingdom there, initially calling it Sipje in reference to his ten advisors, a name which later evolved into Baekje.
The Founding of Baekje
Biryu's settlement at Michuhol soon faltered. The salty coastal soil proved poor for agriculture, and the marshland made the area difficult to develop. Realizing his mistake, Biryu traveled to Wiryeseong and saw that Onjo's kingdom was thriving. Overcome with shame, Biryu took his own life. His followers then migrated to Wiryeseong and submitted to Onjo's authority, consolidating the young kingdom.
Onjo proved an active ruler. The Samguk Sagi records his construction of walls and defenses, establishment of ritual sites, and negotiations with the neighboring Mahan confederacy. He is described as moving his capital within the Wiryeseong region to strengthen defenses, and as expanding Baekje's territory through diplomacy and military action. The text records his reign as lasting from 18 BCE to 28 CE, placing him in the foundational age of the Three Kingdoms period alongside the origins of Goguryeo and Silla.