Princess Heungbang was a Goryeo Royal Princess as the youngest daughter[1] of King Taejo and Queen Sinmyeong.
She was also the younger sister-in-law of King Gyeongsun of Silla, who later married her half brother, Prince Wonjang.
[1] Princess Heungbang had a son Prince Heungbang and a daughter Lady Daemyeong, who would become King Gyeongjong's fifth wife.
The use of the title Gung-ju for the king's daughter began with the case of Princess Heungbang.
In addition, the title Gung-ju was also used for princesses, and this form continued throughout the Goryeo periods.