The Political Status of Baekga during the Reign of King Dongseong of Baekje and the Background of the King's Assassination

Baek Ga emerged as a newly prominent aristocratic figure during the reign of King Dongseong, notable for his appointment to the post of Wisa Jwapyeong(衛士佐平), the official in charge of the royal guards. Given the continuing political instability in the aftermath of King Munju’s assassination and the rebellion of Hae Gu, Baek Ga’s assumption of the responsibility for the king’s personal security indicates that he was both militarily competent and a powerful noble who enjoyed the king’s trust. After being appointed Wisa Jwapyeong in 486, Baek Ga retained the position for fifteen years. However, he was suddenly reassigned to Garim Fortress. This abrupt transfer is commonly understood as a consequence of Baek Ga’s resistance to King Dongseong’s political agenda—particularly his opposition to the king’s proposed relocation of the capital to Sabi. Since Baek Ga is presumed to have originated from the Woongjin region, his reassignment is widely interpreted as reflecting conflict over the relocation plan. Attention should be paid not only to this conflict but also to the significance of the position of Wisa Jwapyeong. This office was responsible for protecting the king in close proximity and shared military authority with the Byeonggwan Jwapyeong (Minister of Military Affairs). While the ultimate authority to appoint the Wisa Jwapyeong rested with the king, the position itself was typically held by a top-ranking noble, suggesting that broader aristocratic interests were also involved in such appointments. King Dongseong appears to have attempted a reorganization of Baekje’s military system through the adoption of Chinese-style command structures. Titles such as Yeonggun(領軍) found in the Nihon Shoki and Dojanggun(都將軍) mentioned in the Book of Southern Qi likely originated from designations used for imperial guard commanders during China’s Northern and Southern Dynasties. The concentrated appearance of such titles during King Dongseong’s reign indicates that he sought to establish and operate a personal royal guard using a Chinese-style military hierarchy. This policy orientation increasingly came into conflict with the role and authority of the Wisa Jwapyeong. In an apparent attempt to curtail Baek Ga’s influence, King Dongseong forcibly reassigned him to Garim Fortress, thereby removing him from the royal capital. Baek Ga’s transfer can be interpreted as a product of the king’s determination to implement reforms to the existing military system. However, this decision ultimately led to Baek Ga’s assassination of King Dongseong, which in turn created the opportunity for King Muryeong’s ascension to the throne.