After the carnage of the Kalinga war in the 3rd century BCE, the emperor Ashoka converted to Buddhism. A traditional account says 84,000 stupas were built across his empire; only a handful survive. The Great Stupa at Sanchi preserves both Ashoka's original core and the additions of later dynasties.

A stupa is a hemispherical mound built to enshrine relics of the Buddha, crowned by a symbolic parasol (chattra). The Sanchi dome (anda) is roughly 36 metres across. The visual wealth lies in the four ceremonial gateways — toranas — that rise on the cardinal axes. These gateways were added in the 1st century BCE, under the post-Mauryan Shunga and early Satavahana dynasties. Their lintels are packed with relief: Jataka tales (the Buddha's former lives), crowd scenes, elephants and lions.

The critical point: in early Buddhist art the Buddha is not shown in human form. He is represented by symbols — an empty throne, a pair of footprints, a wheel, a bodhi tree. This 'aniconic' tradition will only give way in the 1st–2nd centuries CE, in the schools of Gandhara and Mathura, where a human Buddha appears. Sanchi preserves the visual logic of Buddhist art at the moment just before that change.