She served as guardian for her brother , Danjong of Joseon , when he ascended the throne underage .
Princess Gyeonghye ( 1435 -- 1473 ) , also known as Princess Pyeongchang before her marriage , was a Joseon princess and the eldest child of Munjong of Joseon .
She served as guardian for her brother , Munjong of Joseon     , when he ascended the throne underage .
Princess Gyeonghye ( 1435 -- 1473 ) , also known as Princess Pyeongchang before her marriage , was a Joseon princess and the eldest child of Munjong of Joseon .