Lobed mirror with a dragon and clouds, China, mid-Tang dynasty, first half of 8th century. Cast bronze. Purchase, Freer Gallery of Art, F1938.8 © 2017 Smithsonian Institution

A coiled dragon with a pearl (represented by the central knob on the mirror) amidst clouds is a prominent motif in Tang mirror decoration. This mirror is distinguished by its imposing size (with a diameter of more than eight inches) and its forceful presentation of the scaly, three-clawed dragon with its tail and one rear leg intertwined. Associated with imperial authority and prestige, mirrors such as this were exchanged as gifts between the Tang emperor Xuanzong (reigned 713–755) and his court officials. Legends hold that such mirrors possessed the power to summon rain. They were conventionally cast on the fifth day of the fifth month, according to the Chinese lunar calendar, a point when fire, one of the five elements in the Chinese cosmology, was thought to be most active.