Bonhams is facing calls to withdraw a Roman plate from an upcoming sale after a researcher has renewed claims that it is stolen. The allegations have reignited a debate over whether auction houses can—and should—access archives of trafficked antiquities from relevant authorities.

The silver plate depicting a Roman river god dates to the third century CE and is estimated to fetch between £20,000 and £30,000 ($25,159 and $37,738) at Bonham’s December 5 antiquities sale in London. Christos Tsirogiannis, an archaeologist who researches looted antiquities, alleges that the plate was among works held by the now convicted dealer Gianfranco Becchina.

The auction house has denied the claim, noting that it came from a well-known “princely collection,” which a spokesperson explained as “an exceptional collection assembled by an individual.” The provenance notes for the work state that it was acquired from the current consignor at Cultura in Basel in October 2002. The work was on loan to the Antikenmuseum Basel from October 24, 2002, to July 31, 2018 and was exhibited there.

“We have strict procedures in place to help us ensure that we offer for sale objects that we are legally able to sell,” said the Bonhams spokesperson in response to Tsirogiannis’s claims, adding that the provenance of all works for sale is listed in the sale catalog and available in public domain.

The plate was previously sold by Bonham’s in a July 4 sale, ahead of which Tsirogiannis also called for it to be pulled from the sale, based on his evidence suggesting that the piece was among the bulk seized from Becchina, who was convicted in Italy in 2011 of illegally dealing in antiquities; he has also been convicted twice in Greece since then.

Photos of the Roman silver plate, unrestored, in the Becchina archive. Courtesy of Christos Tsirogiannis.

The evidence reportedly came from Becchina’s archive, which was shared with Tsirogiannis by Paolo Giorgio Ferri, the late Italian prosecutor famous for tracking down traffickers of looted antiquities and recovering tens of thousands of them, primarily Greco-Roman artifacts. Records of an object resembling the shape of the plate was said to be part of a group of Roman silver objects that Becchina acquired for $1.6 million.

Bonham’s similarly denied the claims brought by Tsirogiannis ahead of the July auction and the sale went ahead. The plate achieved £74,000 (around $94,720) then. However, the buyer failed to pay for the lot on time, according to the auction house, which is re-offering the lot in their December sale at the request of the consignor.

Tsirogiannis noted that the work’s previous sale in July just was not recorded in the provenance listed for the lot. In response, Bonhams noted that not mentioning the previous sale is a standard practice across the major auction houses if the sale resulted in the piece not selling, or the payment not being made.

The archaeologist is also claiming that another lot featured in the same sale, a Roman marble portrait bust of Emperor Hadrian, estimated to fetch £80,000 to £120,000 ($100,515 to $150,773), is connected with Becchina.

A monumental Roman marble portrait bust of the Emperor Hadrian, Hadrianic Period, reign 117–138 CE. Courtesy of Bonhams.

“Bonhams appears not to have conducted basic provenance research, which would involve checking with the relevant authorities on whether particular antiquities may have been looted,” Tsirogiannis told the Guardian, noting that the Becchina files are also in the hands of the Italian and Greek authorities.

Tsirogiannis leads illicit antiquities trafficking research for the Unesco chair on threats to cultural heritage at the Ionian University in Corfu. He has reportedly identified more than 1,700 looted items in the art trade over the past 18 years. By publicizing these claims in the media, he has successfully led major auction houses to withdraw dubious lots from sales over the years. He said that auction houses should check with the authorities’ archives to ensure that antiquities that are up for sale are not trafficked items. Auction houses, however, maintain that they do not have access to such archives.

“Bonhams has repeatedly asked Christos Tsirogiannis for access to the archive. We feel his efforts to address the antiquities trade would be far more effective if he allowed auction houses access to the archives before the items were offered for sale on behalf of consignors,” said an auction house representative. “In the case of these items, the authorities were aware of it, investigated it, and decided not to take matters any further.”

A photo of Hadrian’s marble bust, unrestored, in the Becchina archive. Courtesy of Christos Tsirogiannis.

Tsirogiannis said via email that he was never approached by any auction house to offer assistance in provenance checking. He pointed out antiquities market players, including auction houses and dealers, often presented “a fake argument” claiming that they do not have access to these archives. He noted that market players can access the archives through the authorities, and all they need to do is send “a simple email” with the basic information required about the objects in question and images of the objects as an attachment. The authorities should search the archives for them promptly and free of charge.

Furthermore, he claimed that “members of the antiquities market still choose not to contact the authorities to check the objects they are about to offer,” even months before they put together the catalog of their scheduled auction or sale. “Then, when they are found with stolen antiquities, they claim publicly that they do not have access to the archives,” Tsirogiannis said, adding that, “in reality, they avoided [contacting the] relevant authorities as the most basic part of their due diligence, which they advertise but they do not exercise.”

Several market insiders familiar with the inner workings of the antiquities market said that Tsirogiannis’s allegations against auction house workers and dealers for not doing their due diligence properly were unjust. They said access to these archives through governmental authorities is not as straight forward as it sounds and that such an infrastructure for provenance checking is not in place. Since the archives are not readily available in the public domain or accessible databases such as Art Loss Register, it can create challenges for carrying out due diligence work.

However, Tsirogiannis, who has advised on private collectors on provenance issues in the past, said he was open to collaborate with those who have “high ethical standards and a clear position against antiquities trafficking.”