The mysterious image of a deerlike animal gazing up at the moon among clouds has been variously interpreted over many centuries. The animal, lying down with one foreleg extended and looking back, originated as a djeiran, or Central Asian antelope. Commonly appearing on Sogdian silver from the 600s onward, the motif migrated via the trade routes to northern China. There, during the Jin and Yuan (1279–1368) dynasties, it was very popular and always depicted with the moon supported by clouds. Chinese writers often identify the djeiran as the mythical rhinoceros (xi'niu) that is said to gaze at the moon, or as the cow of Wu "panting upon seeing the moon."