King Myeongjong of Goryeo vs Sejo of Joseon

After deposing King Uijong, the military leaders installed King Myeongjong, a younger brother, as the new monarch. Myeongjong had no real power; all decisions were made by the military regime, first under Jeong Jung-bu and later under Gyeong Dae-seung.

During Myeongjong's reign, numerous peasant uprisings broke out across Goryeo due to heavy taxation and oppression. The military regime brutally suppressed these revolts, including the major rebellion led by Mang-i and Mang-so-i in 1176.

King Myeongjong's reign saw the rise of the Choe family military dictatorship under Choe Chung-heon. The king remained a figurehead while Choe controlled the government, army, and royal succession. This period established the Choe regime's dominance.

Choe Chung-heon forced King Myeongjong to abdicate in favor of his younger brother, King Sinjong. Myeongjong was exiled to Ganghwa Island. This demonstrated the complete control of the Choe regime over the monarchy.

Grand Prince Suyang (later Sejo) staged a coup, forcing his nephew King Danjong to abdicate. Sejo assumed the throne, initiating a reign marked by consolidation of power and elimination of rivals.

Sejo discovered a plot by six loyalist ministers to restore Danjong. He had them executed, along with their families, in a brutal purge that eliminated opposition to his rule.

Sejo ordered the murder of his deposed nephew Danjong, who was then 16. This act removed the last legitimate claimant to the throne and secured Sejo's dynasty.

Sejo led military campaigns against Jurchen tribes in the northern border regions. These campaigns secured Joseon's northern frontier and expanded territory.

Sejo initiated the compilation of the Gyeongguk Daejeon, a comprehensive legal code that would later be completed under Seongjong. This code systematized Joseon's government and laws.