The Yesong Controversy was a significant political conflict during the Joseon Dynasty, centered around the funeral rites for King Hyojong, who died in 1659. The debate involved the Westerners faction, led by Song Si-yeol, and the Southerners faction, led by Heo Jeok, and revolved around the duration Queen Jangryeol, King Injo's second wife, should observe mourning for Hyojong. The Westerners argued for a one-year mourning period, customary for a second stepson, while the Southerners advocated for a three-year period, reflecting Hyojong's status as King Injo's successor. King Hyeonjong, Hyojong's successor, ultimately sided with the Westerners, enforcing a one-year mourning period. However, he retained Heo Jeok as Prime Minister to maintain balance and prevent the Westerners from overpowering royal authority. This decision temporarily appeased both factions, but the underlying tensions remained.

The issue resurfaced with the death of Queen Inseon in 1674. The Southerners and the Westerners disagreed again on the mourning period, this time for Queen Jaeui. Hyeonjong sided with the Southerners, leading to their rise as the major political faction. The controversy continued even after Hyeonjong's death in 1675 and was only settled by his successor, King Sukjong, who banned further debate on the matter. The dispute affected the official history of Hyeonjong's era, initially written by the Southerners but later revised by Westerners.

During Hyeonjong's reign, notable events included the departure of Dutchman Hendrick Hamel from Korea in 1666. Hamel's writings about his experiences in Korea introduced the Joseon Dynasty to European readers. Additionally, Korea suffered a severe famine in 1670-1671, causing widespread hardship. Hyeonjong abandoned Hyojong's ambitious plans for northern conquest, recognizing the Qing Dynasty's growing power. He continued military expansion and national reconstruction efforts and encouraged advancements in astronomy and printing. Hyeonjong also enacted laws to prohibit marriage between relatives and those with the same surnames. His reign ended with his death in 1674, and he was succeeded by his son, King Sukjong.