A review of 96 items from the Kingdom of Benin in Swiss museums found strong proof that more than half of the artifacts were looted by British soldiers in the 19th century.

The Swiss Benin Initiative (SBI) released a research report this week that revealed that 21 Benin items in eight Swiss museums were stolen based on written records like burn marks that “provide a direct link to the fateful events of 1897.”

Researchers found “strong evidence” of looting for 32 objects that did not have written proof linking them to 1897 but were still considered to be court or royal artworks produced exclusively for the palace.

Read: Oxford Uni: 97 artifacts looted in 1897 to be returned to Nigeria

“We may assume with considerable certainty that they were violently appropriated in 1897 when the palace was occupied and sacked by the British troops,” the report’s authors wrote.

One example is found at the Rietberg Museum, a brass hip pendant mask that bears on its backside an inventory number of William D. Webster. According to the museum’s latest research, the London art dealer was tasked with selling the seized Benin artifacts on behalf of the British colonial administration.

The SBI report also reveals that private collectors, along with international and Swiss art markets, played a pivotal role in how the artifacts entered the museums’ collections.

In June 2020, the eight Swiss museums willingly launched the SBI with the Federal Office of Culture's funding support. The goal was to investigate which of the publicly owned Benin items were directly connected with the 1897 events, when British empire troops were sent to steal artifacts from what is today Nigeria, in retaliation for the death of unarmed British explorer James Philips and many others on his mission after their expedition to Benin.

The thousands of looted artifacts taken from the Benin kingdom are widely known as the Benin Bronzes. While the exact number is unknown, it is believed to be more than 3,000.

A press release says the goal of the SBI research project “was to shed light on the contexts of the acquisitions back in the colonial days and to understand how Switzerland became involved in the trade with looted art from Benin City.”

Read: New York Museum Returns 3 Artworks Looted from Nigeria

Notably, the SBI project worked with Enibokun Uzébu-Imarghiabge, a Nigerian historian who looked into the oral history of the objects and conducted interviews with local experts.

The research results led the SBI to say that the Swiss museums said they are open to a transfer of ownership and possible repatriation of the 53 looted and likely looted artifacts.

Few institutions have formally repatriated their Benin Bronzes, despite the fact that Nigerian officials have encouraged more museums to do so.

If the Benin Bronzes currently in Swiss museums are eventually repatriated to Nigeria, they would likely be sent to a museum that is being constructed in Benin City specifically for them. The Edo Museum of West African Art, set to open in 2025, is expected to host the most comprehensive collection of Benin Bronzes to date.