King Gwangjong

Gwangjong (925–975) was the fourth ruler of Goryeo, who worked to curb the power of regional aristocrats and strengthen royal authority. He enacted the Slave Review Act, which examined and freed people who had been unlawfully made slaves, and in 958 introduced the civil service examination system to recruit officials by merit. He also proclaimed himself emperor and adopted his own era names, elevating the standing of the throne.