Birth name
Korean name
Hangul	광종
Hanja
Revised Romanization	Gwangjong
McCune–Reischauer	Kwangjong
Hangul	왕소
Hanja
Revised Romanization	Wang So
McCune–Reischauer	Wang So
Courtesy name
Hangul	일화
Hanja	日華
Revised Romanization	Ilhwa
McCune–Reischauer	Ilhwa
Posthumous name
Hangul	홍도선열평세숙헌의효강혜대성대왕
Hanja
Revised Romanization	Hongdoseon-yeolpyeongse sukheon-ui hyoganghye daeseong dae-wang
McCune–Reischauer	Hongdosŏnyŏlp'yŏngse sukhŏnŭi hyokanghye taesŏng taewang

Gwangjong (925 – 4 July 975), personal name Wang So, was the fourth king of Goryeo.

Gwangjong was born in 925 as Wang So, fourth son of king Taejo, who had founded Goryeo in 918. His mother was queen Sinmyeongsunseong of the Chungju Yu clan, who also gave birth to princes Wang Tae, Wang Yo, Wang Jeong, and Jeungtong, and princesses Nangnang and Heungbang. Moreover, Gwangjong had twenty half-brothers and seven half-sisters from his father's other marriages.

As he had three older brothers, Mu, Tae and Yo, he was far from the succession to the throne; however, Wang Tae died early on, and Wang Mu died in 945, three years after being crowned king, leaving the throne to Wang Yo, who ruled Goryeo for four years as Jeongjong. Before dying, he decided to make Wang So his heir instead of his one and only son, prince Gyeongchunwon.

According to contemporary Choe Seungno, Gwangjong "was careful and laconic, but bold if he had to seize an opportunity." He had excellent appearance and qualities, and he received a special love from his father.

During his time as a prince, he played a big role in removing Wang Gyu's and Park Sul-hee's opposing forces, and gave a great contribution in the crowning of Wang Yo as Jeongjong.

When Gwangjong ascended the throne on April 13, 949, at the age of 25, the kingdom of Goryeo was unstable: to unify the Later Three Kingdoms, his father Taejo made alliances with powerful and influential families through marriages. Keeping them satisfied was paramount, as those families all had their own armies and could rebel at any time. For this reason, Gwangjong felt the need to consolidate the power of the king and made the creation of an absolute monarchy the purpose of his entire government. To avoid an increase in the power and in the influence of noble families, he refused to marry a woman from a noble clan, but instead married into the royal family: queen Daemok was his half-sister, whose mother came from the Hwangju family of Hwangbo, while his second wife, princess Gyeonghwagung, was born by his elder half-brother Hyejong, second king of Goryeo, and his first wife, of the Im family of Chinju. Along with studying Taizong of Tang's book Difan (Chinese: 帝範; literally: "Rules for an emperor") to better understand what to do, as he found many similarities between his situation and that of Taizong, Gwangjong rewarded all those who contributed to the progress of Goryeo, also making much effort to maintain good diplomatic relations with neighboring countries. This allowed him to concentrate power from within and without the court, and, seven years after the start of his reign, enact a series of reforms to promote a stable and royal-centered political system, and to expand economy and military.

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Wikipedia