The world’s most famous collection of African art arrived in Britain after a spectacular act of colonial violence.

In February 1897, an expeditionary force of 1,200 British soldiers and African auxiliaries crossed the moats and ancient mud walls around the city of Benin, in what is today southern Nigeria. Against defenders armed with swords and muskets, the British-led force deployed machine guns and mobile artillery. Hundreds of Benin residents likely lost their lives.

The British drove into exile—and would later capture—Benin’s oba, or king, a man of semi-deified status known to history by his regnal name, Oba Ovonramwen. They looted the royal compound and packed the most beautiful contents into crates to ship home. Then a fire ignited, perhaps accidentally, perhaps not. Shrines, storehouses, the homes and burial places of past obas—all were destroyed.

Most of the spoils were auctioned off in London. The artworks of carved ivory and cast metal were immediately acclaimed as masterpieces: heads of kings and queen mothers, symbolic animal figures, bells to summon the spirits of the ancestors, metal plaques that depicted court life and the great deeds of the obas. The artistry of the finest pieces is extraordinarily delicate. Seen from the side or bottom, a metalwork from the great age of Benin art, from roughly 1450 to 1650, is astonishingly thin, only about an eighth of an inch thick.

A small but telling mistake of nomenclature conveyed the impact of these African works on the European art world. Most of the Benin metal pieces are made of brass, an alloy of copper and zinc. But in London, the pieces were instantly dubbed “the Benin bronzes”—identifying them with the slightly different alloy of copper and tin used in the traditions most admired by the 19th-century British: those of classical Greece and Renaissance Italy. The misnaming stuck as Benin art headed into public and private collections in Britain and around the world.

In British eyes, justice had been served. The 1897 expedition was ostensibly launched in retaliation for the massacre of a British diplomatic mission to Benin earlier that year. Gruesome evidence of a spasm of human sacrifice by Benin’s rulers immediately before the kingdom’s last battle only strengthened the British conviction that their attack had been righteous.

To the people of Benin, however, the sack of their city reverberated as overwhelmingly as if an invading army had captured London, burned Buckingham Palace and Westminster Abbey, and stolen the contents of the National Gallery and the National Archives. The obas of Benin had once ruled an empire that extended from the Niger River westward hundreds of miles toward what is today Lagos. Ancient Benin had no system of writing other than the stories told in cast brass and carved ivory. Art was the kingdom’s culture, its wealth, its literature, its memory. And then the art was pillaged, leaving behind only ashes where palaces and temples had stood for centuries.