 Over the course of their rule, the Jurchens of Jin quickly adapted to Chinese customs, and even fortified the Great Wall against the rising Mongols.Domestically, the Jin oversaw a number of cultural advancements, such as the revival of Confucianism.After spending centuries as vassals of the Jin, the Mongols invaded under Genghis Khan in 1211 and inflicted catastrophic defeats on the Jin armies.