960-1279 CE
From 960 to 1279 CE, the Chinese achieved heights of refinement that no civilization had yet matched — Song emperors presiding over cities of a million souls, their scholars perfecting movable type and gunpowder, their merchants trading porcelain for spices across the Indian Ocean. Yet military weakness haunted this golden age: first the Khitans took the northern plains, then the Jurchens drove the court south across the Yangtze, and finally the Mongols completed what none had done before — conquering all of China.