Gwangjong of Goryeo vs Mongke Khan

King Gwangjong issued a decree freeing thousands of slaves and commoners who had been unjustly enslaved. This reform weakened the power of the aristocratic clans, strengthened the central monarchy, and increased the tax-paying population of Goryeo.

Gwangjong introduced a Chinese-style civil service examination (gwageo) to select government officials based on merit rather than birth. This reform reduced the influence of the entrenched aristocracy and promoted a more centralized, bureaucratic state.

King Gwangjong ordered the execution or exile of numerous powerful nobles and their families, including many who had opposed his reforms. This violent purge eliminated opposition to his centralization policies but created a climate of fear and resentment among the elite.

Möngke was elected as the fourth Great Khan of the Mongol Empire with the support of Batu and his family, ending a period of regency after Güyük's death. His election was contested by the Ögedeid and Chagataid families, leading to purges.

Möngke launched a massive campaign against the Southern Song dynasty, personally leading the western army while his brother Kublai attacked from the north. The campaign stalled at Diaoyu Fortress, where Möngke died, but it set the stage for Kublai's later conquest.

Möngke ordered a systematic purge of the Ögedeid and Chagataid princes and their supporters, accusing them of plotting against him. Hundreds of nobles were executed, consolidating Möngke's power and centralizing the empire under the Toluid line.

Möngke ordered his brother Hulagu to lead a massive Mongol army into the Middle East to conquer the Abbasid Caliphate and the Ismaili fortresses. This campaign resulted in the destruction of Baghdad in 1258 and the establishment of the Ilkhanate.

Möngke died during the siege of Diaoyu Fortress in Sichuan, possibly from dysentery or a battle wound. His death triggered a succession crisis that led to the division of the Mongol Empire into four khanates.