All views and claims expressed in this article belong solely to the author and have not been independently verified.
I first encountered the business of slavery as an academic while pursuing my Doctoral Studies at University of Manchester on the evolution of financial institutions and markets from antiquity to modern times. I was intrigued by some of the stories I came across in my readings, and with all apologies to the real historians, I am sharing some as we approach Emancipation Day 2026.
Antera Duke was a merchant prince of the Efik, a leader of Duke Town, and between 1785 and 1788 he kept a diary in the trade English of the coast. Oxford University Press published the scholarly edition in 2010. It is, as far as anyone knows, the only surviving day-by-day account written by any slave trader on any continent, and it reads exactly like what it is, a businessman’s diary. Customs duties, called comey, collected from ship captains. Dinners aboard Liverpool vessels, credit disputes and their settlement, and consignments of captives delivered downriver. The tone is flat, commercial, unbothered.
That diary forces the question this piece asks. Before the auction room in Richmond, before the cane piece in Barbados, before even the ship, what was the business? Who ran it, and on what terms? The records are uncomfortable in every direction at once. Start with a fact that may surprise some readers: Europeans almost never captured anyone; they could not. West Africa’s disease environment killed roughly half of newly arrived Europeans within a year, the coast was called the white man’s grave for sound actuarial reasons, and so the Europeans stayed on their ships and in their coastal forts and bought.
The capturing, the marching, and the wholesaling were done by African states and merchant networks. The kingdom of Dahomey, which ran the port of Ouidah under a royal customs regime, the Aro network of Igboland, the canoe-house firms of Bonny and Old Calabar, in which Antera Duke was a principal. Captives were produced by war, by raiding, by judicial condemnation, by seizure for debt, by kidnapping and then sold, at the beach, where the African procurement business met the European shipping business.
I will not soften this, because our history deserves better than flinching, and because the record also shows the other side of it. In 1526 the King of Kongo, Afonso I, a Christian monarch, wrote to the King of Portugal protesting that merchants were seizing his people daily, that “our country is being completely depopulated,” and asking that Portugal send priests and flour for the sacrament, not traders and goods. The letter is on file. So the archive holds both truths at once, African rulers and merchants who ran the supply side for profit, and African rulers who saw precisely what was happening and objected in writing, five centuries ago. The demand shock came from the sea, it industrialized the violence inland. Both facts stand; neither cancels the other.
Now follow the money, because the money is a map of the early modern world. A captive was priced in an “assortment”, a bundle of goods bargained line by line, reckoned in units of account like the trade ounce. And what filled the bundle? Not trinkets! The largest category by value, in David Richardson’s survey of more than ninety English voyages, was textiles, above all Indian cottons, woven in Gujarat and Bengal. Then guns from Birmingham, by the hundred thousand a year at the trade’s height. Iron bars. Brandy and rum. And cowrie shells, harvested in the Maldives and shipped to the Slave Coast by the ton as small currency, the young Olaudah Equiano was sold, he tells us, for 172 of them. A weaver in Bengal, a gunsmith in Birmingham, a shell diver in the Indian Ocean, and a cutlass hand in the Grenadines stood, without knowing one another, in a single supply chain. Prices behaved as prices do, on Richardson’s series, the cost of a captive on the coast rose roughly fivefold across the eighteenth century, as demand outran supply.
The ship itself was a financial instrument. An English slaving voyage was divided into sixty-four shares, and the shareholders were not only great merchants but shopkeepers, clergymen, and widows holding a sixty-fourth as an investment. Mounting a Bristol voyage cost about £8,500 by 1790. The round trip took twelve to eighteen months, and the returns came home mostly as bills of exchange drawn on London. The tidy schoolbook triangle of goods, slaves, and sugar is partly a myth, the real return leg was paper. The cargo was insured, premiums near ten percent of outward costs, the Middle Passage leg priced at about four point eight percent, each human being covered at thirty pounds a head, with insurers not liable for death by illness or by suicide, and losses from insurrection excluded below one-tenth of the cargo’s value. Note what those clauses assume. And note the finding of the economic historians who reconstructed the underwriting books, a slaving voyage was not even an unusually risky policy to write, an East India voyage cost more to insure.
When Parliament first regulated the trade in 1788, it regulated it as what it was, logistics. Dolben’s Act fixed carrying capacity to tonnage, the Liverpool ship Brookes, which had carried 609 people on an earlier voyage, was now lawfully permitted 454, each man allotted a space six feet by sixteen inches. The Act also paid a bonus, one hundred pounds to the captain, fifty to the surgeon, if deaths on the crossing came in under two percent.
Mortality as a key performance indicator, with incentive pay. Across the whole trade, about one captive in seven died at sea. And here is the fact the trade’s defenders never survived: the crews died too. Thomas Clarkson went to the muster rolls and counted in a single year, 216 dead of 910 Bristol slave-trade sailors, more than the rest of Britain’s shipping lost in two. The “nursery of seamen” was a grave for them as well.
So what did it all earn? Here the scholarship delivers its coldest finding. Average British slave-voyage profits, on the best modern estimates, ran at roughly eight to ten percent, and Anstey’s careful series averages 10.2 percent, with enormous variance, and some historians argue the biggest firms did far better in boom years. But the consensus figure is the story, a normal commercial return, shipping money. The trade did not persist for three centuries because it was a bonanza. It persisted because it was ordinary, diversified, insurable, respectable, and open to a clergyman’s widow with one share. Africa, meanwhile, paid a price no ledger recorded. By one careful estimate, the continent’s population in 1850 was half what it would otherwise have been, and modern economics still finds the scar in the data.
The trade was built with ledgers, and it was dismantled with ledgers. Clarkson’s muster-roll tables, the Brookes diagram printed seven thousand times, Equiano’s memoir, the first data-driven human-rights campaign in history, numbers marshalled against power. That is
the tradition this series tries, at its small scale, to stand in. But the diary of Antera Duke will not let me stand there comfortably, and it should not let you. The buyers kept books, the sellers kept books, nobody in this story is safely somebody else. The eye of the needle was the beach where the two ledgers met and every generation since has had to decide, with its own accounts, which side of that beach it is standing on.
Tomorrow, Part 2: the auction room, and the man who banked it.
Professor C. Justin Robinson is Pro Vice-Chancellor and Principal, The UWI Five Islands Campus.
