Since the beginning of the serious study of the history of Buddhist art in the 1890s, the earliest phase, lasting until the 1st century CE, has been described as aniconic; the Buddha was only represented through symbols such as an empty throne, Bodhi tree, a riderless horse with a parasol floating above an empty space (at Sanchi), Buddha's footprints, and the dharma wheel. This reluctance towards anthropomorphic representations of the Buddha, and the sophisticated development of aniconic symbols to avoid it (even in narrative scenes where other human figures would appear), seem to be connected to one of the Buddha's sayings, reported in the Digha Nikaya, that discouraged representations of himself after the extinction of his body. Although there is still some debate, the first anthropomorp