Saṅkassa (Sanskrit Saṅkasya) was a town on the western edge of the Middle Land. Legend says the Buddha descended from the Tavtiṃsa heaven at this place after spending three months teaching abhidhamma to his mother, who had been reborn there after her death. Supposedly three ladders appeared in the sky – a golden one on the right for the god Sakka, a silver one on the left for Brahma and a jeweled one in the middle for the Buddha. Some versions of the legend say that Brahma held an umbrella over the Buddha as he descended from heaven to earth. It is hardly surprising that the so-called miracle at Saṅkassa is not mentioned anywhere in the Tipiṭaka. The place itself is only referred twice in the scriptures and the Buddha only visited it once, passing through it while on his way to somewhere else (Vin.II,299; III,11). Apart from being incredible in itself, the Saṅkassa legend contradicts that Buddha’s prohibition against the public display of psychic powers or miraculous abilities (Vin.II,110-111). There is also no mention in the scriptures of the Buddha mysteriously disappearing from the scene for three months. The Saṅkassa legend’s association with the abhidhamma is a key to its origin and rationale.
The abhidhamma is conspicuous by its absence from the Buddha’s discourses. It is not mentioned as one of the nine branches of the Buddha’s teachings (navaṅga, A.II,103), and the account of the first council describes the recitation of the monastic rules (vinaya) and the discourses (suttas), but not of the abhidhamma (Vin.II,285). As the abhidhamma approach became more popular in the centuries after the Buddha’s passing, and the books of the Abhidhamma Piṭaka were gradually composed, pressure grew to have them considered canonical and included in the Tipiṭaka. An explanation of their origin was needed and thus the legend of the Buddha going to heaven to teach the Abhidhamma Pitaka was created. King Aśoka raised a great stone pillar at Saṅkassa, parts of which can still be seen there. There is, however, no evidence that this pillar was raised to commemorate the legend, which had probably not come into existence at that time. The earliest evidence of the Saṅkassa legend is a sculptural depiction of it from Sanchi which dates from about the 1st century BCE.
‘Excavations at Sankisa,’ Journal of the U.P. Historical Society, 1927.