The Battle of Guju, which occurs in 1019, is the major battle during the Third Goryeo-Khitan War (1018-1019).
“Let us study things that are no more. It is necessary to know them, if only to avoid them. The counterfeits of the past assume false names, and gladly call themselves the future. Let us inform ourselves of the trap. Let us be on our guard. The past has a visage, superstition, and a mask, hypocrisy. Let us denounce the visage and let us tear off the mask."