Sejo of Joseon

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.