고왕국, or the "Goryeo Dynasty," was a Korean kingdom that lasted from 918 to 1392. It was founded by Wang Geon, who later became known as King Taejo. The dynasty is notable for its cultural achievements, including the creation of the Korean script and advancements in ceramics, particularly the famous celadon pottery. During the Goryeo period, the kingdom faced various challenges, including invasions from the Mongols. Despite these difficulties, Goryeo maintained a centralized government and promoted Buddhism as a state religion. The dynasty eventually fell to the Joseon Dynasty, marking a significant transition in Korean history.