Lady Seongmu
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, 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.