Lady Seongmu of the Pyeongsan Bak clan () was the daughter of Bak Ji-yun, one of Wang Geon's helper in founding the new Goryeo dynasty who became the 26th wife of Taejo of Goryeo. She gave birth to 4 sons and a daughter who later married King Gyeongsun of Silla,《고려사》〈열전〉- 공주 (태조의 딸) 참고, 성무부인 소생의 공주 이외에도 신명순성왕후 유씨 소생인 낙랑공주가 경순왕과 혼인하였다. but all of her sons died young without left any issue. Since both of Bak Su-mun () and Bak Su-gyeong () were her brothers, she then became the aunt of her husband's 28th and 29th wife.
References
External links 성무부인 on the Encyclopedia of Korean Culture (in Korean).