Of the three ancient kingdoms of the Three Kingdoms Period—Baekje, Goguryeo, and Silla—Goguryeo was the first to produce and use roof tiles. Goguryeo roof-end tiles are characterized by their bold designs and dynamic relief decorations, as evidenced by this particular tile, which features a carving of a hideous monster. The wide eyes, fleshy nose, gaping mouth, and sharp teeth of the beast are expressed in high relief. Such monstrous faces were believed to ward off evil spirits, so this motif was often used to adorn buildings and tombs, as well as in designs with some supernatural meaning.