At dawn a courier burst into the Goguryeo palace, shouting that the general had come. Yeon Gaesomun (연개소문) strode through the main hall and killed King Yeongnyu (영류왕) with his sword.
Goguryeo (고구려) was split between court nobles who wanted talks with Tang and frontier commanders who feared being absorbed. Yeon Gaesomun was a frontier strongman who thought surrender would end their world. So he struck fast, purged dozens of pro-Tang officials, and set up military rule from the capital.
The move shocked people, but it also forced a strange kind of unity. When Emperor Taizong of Tang launched a huge invasion in 645, Yeon led a hard, organized defense. Commanders like Yang Manchun (양만춘) held Ansi fortress and laughed off siege engines, and Tang had to pull back after massive cost.
Yeon kept Goguryeo fighting for about two decades, and the state lived on because the army held together under his rule. Then he died around 666 and his sons turned on each other. That family war split the country and let the Tang-Silla alliance sweep in and take Goguryeo in 668.
The whole story reads like a grim bargain. Yeon killed a king to stop foreign takeover, and his rule bought time, not a future. His coup made resistance possible, and his heirs made conquest easy.
It feels familiar now, the way a violent grab for power can be sold as protection and end in collapse. Text this to someone when you hear a leader say they need to break rules to save the nation.