Goryosa (The History of Goryeo) recorded that a pavilion named Yangijeong was built in 1157 (the 11th year of King Uijong’s reign), and that its roof was covered with celadon tiles. The roof tiles used at that time must have been very similar to this celadon tile, which gives us a fairly clear idea of how the celadon roof tiles of palace structures might have looked in those days.