By the Han empire, concepts of the cosmos were changing basically from that of the ‘Four Quarters’ (Si fang) to the ‘Five Phases’ (Wu xing), with a place for emperors to act as an essential pivot in the interlocking relationships of Heaven, Earth and Man. Differing views of the duty of monarchs may be discerned, e.g., in the memorials of Dong Zhongshu and the chapters of the Huainanzi, and the underlying questions could lead to antagonisms between emperors and kings, or between high-ranking officials of government and scholars of traditional writings. The part that individual Han emperors played in determining decisions of state may well be limited to a few instances. While it may be questioned how far they were conscious of the intellectual basis that supported their authority with its implied responsibilities, Wang Mang tried to exploit a view of the cosmos to assert his claim to power.