'The Piprahwa finds appear to include genuine relics from the Buddha's cremation, thus lending support to the historical reliability of the Mahaparinibbana Sutta and by implication the Early Buddhist Texts as a whole' (From The Authenticity of the Early Buddhist Texts by Bhikkhu Sujato & Bhikku Brahmali, Oxford University Press 2014)
Excerpt from Mahaparinirvana Sutra
31. And it came about that when the body of the Blessed One had been burned, no ashes or particles were to be seen of what had been skin, tissue, flesh, sinews, and fluid; only bones remained. Just as when ghee or oil is burned, it leaves no particles or ashes behind, even so when the body of the Blessed One had been burned, no ashes or particles were to be seen of what had been skin, tissue, flesh, sinews, and fluid; only bones remained. And of the five hundred linen wrappings, only two were not consumed, the innermost and the outermost.
32. And when the body of the Blessed One had been burned, water rained down from heaven and extinguished the pyre of the Blessed One, and from the sala trees water came forth, and the Mallas of Kusinara brought water scented with many kinds of perfumes, and they too extinguished the pyre of the Blessed One.
And the Mallas of Kusinara laid the relics of the Blessed One in their council hall, and surrounded them with a lattice-work of spears and encircled them with a fence of bows; and there for seven days they paid homage to the relics of the Blessed One with dance, song, music, flower-garlands, and perfume, and showed respect, honor, and veneration to the relics of the Blessed One.
Partition of the Relics
33. Then the king of Magadha, Ajatasattu, son of the Videhi queen, came to know that at Kusinara the Blessed One had passed away. And he sent a message to the Mallas of Kusinara, saying: "The Blessed One was of the warrior caste, and I am too. I am worthy to receive a portion of the relics of the Blessed One. I will erect a stupa over the relics of the Blessed One and hold a festival in their honor."
34. And the Licchavis of Vesali came to know that at Kusinara the Blessed One had passed away. And they sent a message to the Mallas of Kusinara, saying: "The Blessed One was of the warrior caste, and we are too. We are worthy to receive a portion of the relics of the Blessed One. We will erect a stupa over the relics of the Blessed One and hold a festival in their honor."
35. And the Sakyas of Kapilavatthu came to know that at Kusinara the Blessed One had passed away. And they sent a message to the Mallas of Kusinara, saying: "The Blessed One was the greatest of our clan. We are worthy to receive a portion of the relics of the Blessed One. We will erect a stupa over the relics of the Blessed One and hold a festival in their honor."
40. But when they heard these words, the Mallas of Kusinara addressed the assembly, saying: "The Blessed One has passed away in our township. We shall not part with any portion of the relics of the Blessed One." Then the brahman Dona spoke to the assembly, saying:
One word from me, I beg you, sirs, to hear! Our Buddha taught us ever to forbear; Unseemly would it be should strife arise And war and bloodshed, over the custody Of his remains, who was the best of men! Let us all, sirs, in friendliness agree To share eight portions— so that far and wide Stupas may rise, and seeing them, mankind Faith in the All-Enlightened One will find!
"So be it, brahman! Divide the relics into eight equal portions yourself."
And the brahman Dona said to the assembly: "So be it, sirs." And he divided justly into eight equal portions the relics of the Blessed One, and having done so, he addressed the assembly, saying: "Let this urn, sirs, be given to me. Over this urn I will erect a stupa, and in its honor I will hold a festival." And the urn was given to the brahman Dona.
41. Then the Moriyas of Pipphalivana came to know that at Kusinara the Blessed One had passed away. And they sent a message to the Mallas of Kusinara, saying: "The Blessed One was of the warrior caste, and we are too. We are worthy to receive a portion of the relics of the Blessed One. We will erect a stupa over the relics of the Blessed One and hold a festival in their honor."
"There is no portion of the relics of the Blessed One remaining; the relics of the Blessed One have been divided. But take from here the ashes." And they took from there the ashes.
So it came about that there were eight stupas for the relics, a ninth for the urn, and a tenth for the ashes.
And thus it was in the days of old.
43. Eight portions there were of the relics of him, The All-Seeing One, the greatest of men. Seven in Jambudipa are honored, and one In Ramagama, by kings of the Naga race. One tooth is honored in the Tavatimsa heaven, One in the realm of Kalinga, and one by the Naga kings. Through their brightness this bountiful earth With its most excellent gifts is endowed; For thus the relics of the All-Seeing One are best honored By those who are worthy of honor - by gods and Nagas And lords of men, yea, by the highest of mankind. Pay homage with clasped hands! For hard indeed it is Through hundreds of ages to meet with an All-Enlightened One !