Choe Yeong
When a Ming messenger came to Goryeo in 1388 (the 14th year of King U) to demand the return of a significant portion of Goryeo's northern territory, General Choe Yeong seized the opportunity and played upon the prevailing anti-Ming atmosphere to argue for the invasion of the Liaodong Peninsula (Goryeo claimed to be the successor of the ancient kingdom of Goguryeo; as such, restoring Manchuria as part of Korean territory was a tenet of its foreign policy throughout its history).