King Gwangjong
Fourth king of Goryeo, who strengthened royal power with the Slave Review Act, the civil service examination and imperial titles
After keeping a low profile early in his reign, he weakened the economic and military base of the local magnates with the Slave Review Act of 956, freeing people they had wrongfully enslaved. In 958, on the advice of Ssanggi, a naturalised official from Later Zhou, he introduced the civil service examination, and in 960 he fixed official robes in purple, crimson, scarlet and green by rank. He called himself emperor and used his own era names, Gwangdeok and Junpung, naming Gaegyeong the imperial capital. He purged the merit subjects and magnates who opposed him and made Gyunyeo abbot of Gwibeopsa.