After the Buddha's passing and cremation, his ashes were divided into eight and each portion was interned under a large hemispherical earthen mound, as was the custom of the time. People would pay their respects to these mounds until eventually they came to be seen as symbols of the Buddha himself. In time the simple earthen mounds evolved into masonry structures, sometimes of great size and beautifully decorated. Today ståpas usually contain real or supposed relics of the Buddha or some great saint or articles used by them and are common objects of devotion in all Buddhist countries. The world's largest such monument is the Jetavana Stupa built by King Mahàsena towards the end of the 4th century in Anuràdhapura, the ancient capital of Sri Lanka. This huge monument was originally 160 meters high; its present height up to the broken pinnacle is 70 meters and it has a diameter of 109 meters. It has been calculated that Jetavana Stupa contains 62 million bricks and weighs 657,000 tons. It sits on a huge paved terrace 173 meters square which could have accommodated up to 30,000 devotees on special occasions.
A common misconception is that the Buddha did not allow statues or stupas and this was a later innovation. This is not correct. The Buddha advised that stupas should be done.
26. "The body of a universal monarch, Ananda, is first wrapped round with new linen, and then with teased cotton wool, and so it is done up to five hundred layers of linen and five hundred of cotton wool. When that is done, the body of the universal monarch is placed in an iron oil vessel, which is enclosed in another iron vessel, a funeral pyre is built of all kinds of perfumed woods, and so the body of the universal monarch is burned; and at a crossroads a stupa is raised for the universal monarch. So it is done, Ananda, with the body of a universal monarch. And even, Ananda, as with the body of a universal monarch, so should it be done with the body of the Tathagata; and at a crossroads also a stupa should be raised for the Tathagata. And whosoever shall bring to that place garlands or incense or sandalpaste, or pay reverence, and whose mind becomes calm there — it will be to his well being and happiness for a long time.
27. "There are four persons, Ananda, who are worthy of a stupa. Who are those four? A Tathagata, an Arahant, a Fully Enlightened One is worthy of a stupa; so also is a Paccekabuddha, and a disciple of a Tathagata, and a universal monarch.
28-31. "And why, Ananda, is a Tathagata, an Arahant, a Fully Enlightened One worthy of a stupa? Because, Ananda, at the thought: 'This is the stupa of that Blessed One, Arahant, Fully Enlightened One!' the hearts of many people will be calmed and made happy; and so calmed and with their minds established in faith therein, at the breaking up of the body, after death, they will be reborn in a realm of heavenly happiness. And so also at the thought: 'This is the stupa of that Paccekabuddha!' or 'This is the stupa of a disciple of that Tathagata, Arahant, Fully Enlightened One!' or 'This is the stupa of that righteous monarch who ruled according to Dhamma!' — the hearts of many people are calmed and made happy; and so calmed and with their minds established in faith therein, at the breaking up of the body, after death, they will be reborn in a realm of heavenly happiness. And it is because of this, Ananda, that these four persons are worthy of a stupa." (Digha Nikaya 16)
King Ashoka is said to have erected 84,000 stupas honoring the Buddha and the Dhamma. He gazed for one full week at the Bodhi Tree. Considering this we can say with certainty that he must have built one in Bodh Gaya honoring the spot of enlightenment, i.e., the Maha Bodhi Temple stupa.
- The Stupa, A.H.Longhurst, 1997.