Glasses that once belonged to Mahatma Gandhi have surfaced after they were left in the mailbox of a U.K. auction house.

The auction house describes the artifact as “a rare and important pair of spectacles,” noting that glasses were an iconic part of Gandhi’s appearance. “It was known that he would often give away his old or unwanted pairs to those in need or those who had helped him.”

It is thought that the seller’s uncle was given the glasses when he was working in South Africa for British Petroleum. “It can be presumed that these were gifted by way of thanks from Gandhi for some good deed,” East Bristol Auctions, explains. “A note from the vendor is included.”

The glasses have a pre-sale estimate of 10,000 to 15,000 U.K pounds ($13,067 to $19,600). The leading online bid on the auction house’s website is 50,000 U.K. pounds ($65,334). 

The auction takes place on Aug. 21.

Statues of Gandhi have sparked controversy in recent years. In 2019, student activists in Manchester, U.K., urged the city to reject a Gandhi statue, citing what they describe as his “well-documented anti-black racism,” according to a BBC report.

In the U.K. city of Leicester, the mayor has resisted calls to remove a statue of Gandhi. In 2018, a statue of Gandhi was removed from a university in Ghana over claims of racism.