On Wednesday, a cache of dazzling jewels linked to the Buddha's mortal remains, which have been hailed as one of the most astonishing archaeological finds of the modern era, will go under the hammer at Sotheby's in Hong Kong.

For over a century these relics, unearthed from a dusty mound in northern India in 1898, have sat largely unseen, cradled by a private British collection.

Now, as the gems prepare to leave the custody of their keepers, they are stirring not just collectors' appetites but also some unease.

They come from a glittering hoard of nearly 1,800 pearls, rubies, topaz, sapphires, and patterned gold sheets, first glimpsed deep inside a brick chamber in present-day Uttar Pradesh in India, near the Buddha's birthplace.

Their discovery – alongside bone fragments identified by an inscribed urn as belonging to the Buddha himself – reverberated through the world of archaeology. Nicolas Chow, chairman of Sotheby's Asia and worldwide head of Asian Art, believes this is "among the most extraordinary archaeological discoveries of all time".

Yet as these relics now face the glare of the auction room, experts tell the BBC that a question hangs heavy: can the sale of treasures so intimately woven into India's sacred past be considered ethical?

In 1898, William Claxton Peppé, an English estate manager, excavated a stupa at Piprahwa, just south of Lumbini, where the Buddha is believed to have been born. He uncovered relics inscribed and consecrated nearly 2,000 years ago.

Historians agree these relics, intact until then, are the heritage of both the Buddha's Sakya clan descendants and Buddhists worldwide. The bone relics have since been distributed to countries such as Thailand, Sri Lanka and Myanmar, where they continue to be venerated.

"Are the relics of the Buddha a commodity that can be treated like a work of art to be sold on the market?" wonders Naman Ahuja, a Delhi-based art historian. "And since they aren't, how is the seller ethically authorised to auction them?

"Since the seller is termed the 'custodian', I would like to ask – custodian on whose behalf? Does custodianship permit them now to sell these........

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