Who owns the Benin Bronzes? The answer has only gotten more complicated.

But that plan soon began to unravel. That same month, the oba said in a written statement to the news media that he should be the sole recipient of the treasures and that anyone who worked with the trust was “an enemy.”

To overcome the oba’s opposition, Nigerian officials developed other options. In March, Abba Tijani, the director general of the museum commission, told a meeting of western museum officials that Nigeria would build a royal museum in Benin City on behalf of the oba and his court to display many of the returned items. Mr Tijani presented a vision for the museum, but no concrete plans, according to two attendees.

Just a few weeks later, President Buhari made his surprise announcement.

In a telephone interview, Mr Tijani said he would challenge the president’s statement. He declined to explain the legal grounds for the dispute, but said a three-page document approving the transfer contained errors.

Nigerian legal experts said in interviews that Mr Tijani must either go to court to force a change or hope Bola Tinubu, Nigeria’s new president, who took office on Monday, makes a statement that overrides his predecessor’s slides.

But while the confusion surrounding the announcement may have put the brakes on new returns, few museum trustees seemed to regret their decision to return the bronzes. Barbara Plankensteiner, the director of the Museum am Rothenbaum, a major ethnographic institute in Hamburg, Germany, said recent events have shown that restitution is a complex process that is likely to be fraught with problems.

“The Benin Bronzes are colonial loot,” she said, and should be returned like any stolen property. It was up to Nigeria to decide what to do with the items in her possession, not former colonial powers, she added.