Overview
Queen Seonjeong of the Chungju Yu clan was a Goryeo royal family member as the paternal granddaughter of Prince Sumyeong and maternal granddaughter of King Gwangjong who became a queen consort through her marriage with her maternal first cousin or paternal second cousin, King Mokjong as his first and primary wife. From this marriage, Queen Seonjeong became the sixth reigned Goryeo queen who followed her maternal clan after Queen Mundeok, her mother.
Life
After her biological father's death, her mother remarried again with Seongjong of Goryeo who believed to raised her since young and treated her not different like his own daughters, which made some believed that the future Queen was King Seongjong's real daughter. Although her age was unknown at this time, but seeing that she married Wang Song (grandson of King Gwangjong and Queen Daemok), they must have been at the similar age or slightly older. They were believed to grew up together almost like a sibling, also Mokjong was said to like to follow her as she had taken care of him since childhood.
In 997, King Seongjong died and was succeeded by her husband. She then followed her grandmother, Queen Sinmyeong's clan. Her mother-in-law, Queen Heonae overtook the new King's throne and became a regent since he was not interested in politics.
Based on Goryeosa, it was written that:
"Mokjong was a King with calm and strong personality, was good at archery and horseback riding, enjoyed alcohol and liked hunting. However, he didn't pay attention to government affairs.”"성품이 침착하고 굳세어 어려서부터 임금의 도량이 있었지만 활쏘기와 말타기를 잘 하고 술을 즐기며 사냥을 좋아하여 정무에 유의하지 않았다"
From Wikipedia (CC BY-SA 4.0).