연개소문
After Goguryeo's victory in the Goguryeo–Sui Wars, in 631 Goguryeo began the fortification of numerous military garrisons after the Tang dynasty, the successor to the Sui in China, began incursions from the northwest. Its construction was supervised by Yeon Gaesomun during the reign of King Yeongnyu. The preparation and coordination was completed in 647, after which Yeon Gaesomun took control of the Goguryeo court in a coup.