Jewels linked to the physical remains of the Buddha are set to be sold at auction, sparking a threat of legal action from India and moral questions about the sale of religious antiquities.
The Piprahwa gems have spent most of the past century in a private family collection after being unearthed in 1898 by a British estate manager.
The relics were found buried with what was believed to be bone fragments and ash of the Buddha.
Sotheby's auction house in Hong Kong will look to sell the collection on Wednesday.
However, New Delhi has threatened Sotheby's with legal action if it does not call off the sale, arguing the auction "violates Indian and international laws as well as UN conventions".
The gems are expected to fetch $20m.
What are the Piprahwa gems?
The Piprahwa gems, made up of thousands of pieces of topaz, pearls, rubies, sapphires and gold sheets, were excavated in 1898 by British estate manager William Claxton Peppé.
He unearthed the jewels and what are believed to be remains of the Buddha from inside a funeral chamber, known as a stupa, in present-day Uttar Pradesh in northern India.
The relics were inscribed and consecrated about 2,000 years ago, during the Mauryan Empire.
Experts agree that the items are linked to both the Buddha's Sakya clan and Buddhists worldwide.
When they were unearthed in 1898, the bones and ash found were separated from the jewels, before being gifted by the British colonial government in India to the King of Siam — modern-day Thailand.
He then distributed some of the bones and ash to Buddhist centres across Asia, including in Myanmar, Thailand and Sri Lanka, where they continue to be venerated.
The rest of the hoard was taken to the colonial museum in Kolkata, before a portion was granted back to the Peppé family.
Sotheby's notes that the Peppé family was granted about a fifth of the total haul.
The family has held on to the collection since, saying that what they have are duplicates.
Ashley Thompson, the chair of South-East Asian art history at SOAS University of London, told ABC's The World program they were not duplicates.
"These are the belongings of Buddhist communities. They are also belongings of humanity," Professor Thompson said.
She said it was clear that both the Buddha's physical remains and the gems were meant to stay together.
"When an exceptionally powerful spiritual master's body is cremated, it is understood that the cremation fire doesn't just reduce that body to bones and ash but also reduces it to these essentially pure crystal-like things," she said.
"They could also have been offerings that were made … in order to ensure merit in perpetuity, effectively assimilating with the bones and ash over time.
"They were all meant to be there together in perpetuity. They are effectively grave goods."
What does India say about the sale?
India's culture ministry posted to Instagram a letter it sent to the owner of the jewels, Chris Peppé.
Mr Peppé is William Claxton Peppé's great-grandson.
In the letter, the Indian government argues that Mr Peppé does not have the authority to sell the relics and that Sotheby's is contributing to "continued colonial exploitation" by going ahead with the sale.
The ministry states that the relics are part of India's "religious and cultural heritage" and has threatened to undertake a public campaign highlighting the auction house's "colonial injustice".
Mr Peppé told the BBC he considered donating the relics but determined that an auction was the "fairest and most transparent way to transfer these relics to Buddhists".
He also wrote: "The colonisation of India by the British had been a source of some cultural shame for me (and continues to be) but, amidst the treasure hunters who hauled their finds back to England, there had also been people focused on the pursuit of knowledge."
In his research, he noted that he discovered that the excavation was an attempt by his great-grandfather "to provide work for his tenant farmers who had fallen victim to the famine of 1897".
[THE WORLD IV]Irrespective of the intellectual value of the collection, Professor Thompson said the case posed significant questions about who owned the gems and whether it was ethical to trade them.
"For Buddhists, they are considered to be highly sacred for their intimate association with the Buddha's body," she said.
"It is certainly achievable to find a home where they are made available for veneration, where they are made available for contemplation."
The Piprahwa gems have featured in several significant exhibitions in recent years, including at The Met in New York.
Sotheby's has been contacted for comment.
