What are the Benin Bronzes, and why are they so controversial?

Known for its beauty and rich metalworking heritage, Benin City was once the beating heart of the Edo kingdom of Benin.

The city – situated in modern-day southern Nigeria – was famed for its specialist bronze-sculpting guilds: groups of skilled artisans that produced works of huge historic and cultural importance.

Upon accession to the throne, the oba (king) of Benin would commission these guilds to craft intricate brass plaques remembering their predecessors’ reign.

It is not clear how many works of art were produced, but experts agree the number was in the thousands.

By the late 19th century, the walls of Benin’s royal palace glittered with a mesmerising array of metalwork.

And then the British arrived.

Oba Ovonramwen Nogbaisi had obstinately refused to recognise Britain’s colonial claim on West Africa, testing the patience of London’s administrators.

When a small UK expedition was ambushed by Nogbaisi’s soldiers, they had the excuse they needed for retribution.

Under the command of Admiral Sir Harry Rawson, 1,200 British troops marched on Benin City in 1897. Chaos ensued.

Historical accounts differ, but the death toll is likely to have been in the thousands, including dozens of women and children.

Much of the beautiful settlement was raised, while marauding British soldiers turned their minds to plunder.

The Oba’s plaques were ripped from the walls of the royal palace and carted off with whatever else looked valuable – regardless of religious or cultural significance.

Together with a priceless collection of pilfered wood and ivory artwork, the haul became known as the Benin Bronzes.

Much of the bounty was back in Britain within months, classified glibly as “spoils of war”.

Artefacts that did not stay with the soldiers who had taken them (the loot was divided up according to rank) invariably found their way to auction houses and private holdings.

A couple even made it to the monarch’s mantelpiece: Queen Victoria was given four stolen objects, including two ivory leopards.

The Bronzes have spread further and further afield over the years, popping up periodically across Europe and the United States.

About 3,000 pieces remain outside of Africa, experts believe, mostly in Western museums and personal collections.

Amid mounting calls for restitution, institutions like the British Museum – holder of the world’s largest Benin collection – have been forced to consider handing artefacts back.

A new museum is being built in Benin City to facilitate this; but as it stands, the Bronzes will only be returned on a temporary, not permanent, basis.

For many campaigners, that simply is not good enough.