Heonjong of Joseon (8 September 1827 – 25 July 1849) was the 24th king of the Joseon Dynasty of Korea. He was the grandson of Sunjo. His father was Crown Prince Hyomyeong (posthumously named Munjo of Joseon), who died at the age of 20 before becoming king and his mother was Queen Sinjeong of the Pungyang Jo clan. Heonjong was born three-years before Hyomyeong's death.
Yi Hwan was born on September 8, 1827, at Gyeongchunjeon in Changdeok Palace. Legend has it that before his birth, his mother dreamt of gifting him a box with a jade-carved tree, and on his birth day, a flock of cranes circled, seen as an unusual sign.
Heonjong became king in 1834 at just 7 years old, succeeding his grandfather, King Sunjo. Despite his reign, political power remained under Queen Sunwon's regency. When he reached adulthood, Queen Sunwon retained control. In 1840, Andong Kim clan took over after the anti-Catholic Gihae persecution.
After ruling for 15 years, King Heonjong passed away in 1849 at 21. He was laid to rest at Gyeongneung tomb in Seoul alongside Queens Hyohyeon and Hyojeong. With no heir, the throne shifted to King Cheoljong, a distant descendant of King Yeongjo.
Following tradition, the records of Heonjong's reign were compiled posthumously in 1851, overseen by Jo In-yeong, his maternal great-uncle.

Who was Heonjong's father, and what was his status in the Joseon Dynasty?
Heonjong's father was Crown Prince Hyomyeong, posthumously named Munjo of Joseon. He passed away at 20 years old before ascending to the throne.

At what age did Heonjong become the king of the Joseon Dynasty, and who held political control during his reign?
Heonjong became king at the age of 7, succeeding his grandfather, King Sunjo. Political power largely remained under the regency of Queen Sunwon.

What significant event led to a change in control in the kingdom during Heonjong's reign?
The Andong Kim clan took control in 1840 following the anti-Catholic Gihae persecution.

Where was Heonjong laid to rest, and who succeeded him on the throne?
Heonjong was buried at Gyeongneung tomb in Seoul alongside Queens Hyohyeon and Hyojeong. King Cheoljong, a distant descendant of King Yeongjo, succeeded him on the throne due to the absence of an heir.

When were the records of Heonjong's reign compiled, and who supervised this process?
Posthumously in 1851, the records of Heonjong's reign were compiled under the supervision of Jo In-yeong, his maternal great-uncle.

Heonjong of Joseon - Wikipedia