Capture of a Slaver off the Coast of Cuba; engraving from 1858

Look and Learn/Illustrated Papers Collection/Bridgeman Images

‘Capture of a Slaver off the Coast of Cuba’; engraving from The Illustrated London News, 1858

In the fall of 1853 Salvador de Castro Jr., a leading Cuban slave trader, traveled to Manhattan to arrange an expedition to West Central Africa to buy slaves and transport them for sale in Cuba. There he met with José Antunes Lopes Lemos, an experienced Brazilian slave trader who had transferred his operations to New York City after Brazil ended its slave trade in 1850. Lemos was one of about a dozen Portuguese and Brazilians who made New York a center of the last decade of the Atlantic slave trade.

Because everything they were doing in the city was illegal—the US had outlawed the slave trade in 1808—the Cuban and Brazilian slave traders took great pains to obscure their activities, something that was relatively easy to do in the bustling port of Lower Manhattan. They hired an intermediary, William Valentine, who in turn hired a German immigrant, James Smith, as captain. Smith went up to Boston, where he purchased the Julia Moulton, a two-hundred-ton vessel built by Tengue and Hall, shipbuilders in Newcastle, Maine, in 1846. In New York Smith claimed that he owned the ship, which he did not. Castro and Lemos stocked it with lumber as well as enough food and water to cross the Atlantic and return, and Smith told customs officials that they were bound for Cape Town, which they were not. Though he later denied it, Smith said he was a US citizen, which enabled the Julia Moulton to fly the American flag on the high seas. This would protect it from British efforts to suppress the slave trade, which Parliament had prohibited in 1807. (By the 1850s the US was the only country that still refused to sign a treaty allowing British cruisers to intercept slaving vessels sailing under its own flag.) Once at sea, the crew used the lumber to build a platform to hold slaves below deck, covered the hatches with metal grilles to create a maritime prison, and headed for Ambrizette, a slaving port on the coast of West Central Africa.

Ambrizette generally trafficked in people enslaved in the Kingdom of Kongo, and most of the captives on the Julia Moulton were likely from Kikongo-speaking communities. Sometimes individuals were enslaved in violent wars between different African groups; others were the victims of conflicts and pressures within their own communities. They were sold to pombeiros—itinerant traders—and taken by canoe or marched to the coast from as far as 250 miles inland. There they were shackled, branded, and caged in wretched pens to await embarkation.

Some 664 Africans were sold to the Julia Moulton, mostly men and boys. The crew worked swiftly to avoid detection by the British navy, transferring the captives to the ship as soon as it arrived on the coast. Once onboard they were stripped naked; the men were sent below, while the women and children—less likely to rebel—were kept on deck. As if all the misery they had suffered were not enough, the nightmare known as the Middle Passage was about to begin.

During the day the four hundred men packed into the slave deck sat on one another’s legs; at night “they lie down upon the deck, on their sides, body to body,” according to the captain. Such conditions were notoriously conducive to disease, and the Julia Moulton was no exception. About a quarter of the captives died, 150 in all, mostly men, most likely from gastrointestinal maladies such as dysentery.

The ship was destined for Cuba, which by the 1850s was the last major importer of enslaved Africans in the Americas. (Of the approximately 226,000 slaves illicitly transported in that last decade, 164,000 went to Cuba.) In mid-June 1854, after forty-five days at sea, the Julia Moulton approached Trinidad de Cuba, a port on the southern coast of the island. On a signal sent by Captain Smith, Cuban traffickers sent out launches to ferry the slaves and crew members ashore. The Cubans then ran the Julia Moulton aground and set it on fire, destroying the evidence of its ignominious final voyage.

At that point things went awry. For a brief moment in 1854 authorities in Madrid decided to crack down on illegal slave trading, making an alliance with Britain in hopes of fending off US imperial designs on Cuba. The governor of Cuba, the reformist captain general Juan de la Pezuela, arrested and imprisoned several of the island’s leading slave traders in Havana, and deposed some corrupt local officials.

The 490 Africans disembarked from the Julia Moulton were intercepted by Spanish authorities at San Carlos, a sugar estate near the port. But the emancipados, as they were known, were not quite emancipated. Instead, they were auctioned off to local sugar planters for five-year contracts.


Meanwhile, Captain Smith and the crew returned to New York. Once there, the first mate, angry at not having been paid, ratted out the captain to the district attorney. Smith was tried, convicted, and sentenced to two years in prison for violation of an 1800 law that made it a crime for US citizens or residents to participate in the foreign slave trade. The trial was a major scandal, producing most of the documentation we have about the voyage of the Julia Moulton.

John Harris tells this story midway into his impressively researched new book, The Last Slave Ships: New York and the End of the Middle Passage. Among its many virtues is a too-modest subtitle. Manhattan is only part of the story. Harris’s description of the “triangular trade” takes readers seamlessly from Cuba to New York to West Central Africa to Cuba and back to New York (with an early side trip to Brazil). Harris raises, if only implicitly, some of the biggest questions historians have asked about the fraught relationship between capitalism and slavery. This is a small book about big things.

In his classic study Capitalism and Slavery (1944), Eric Williams posited a historic reversal of fortune brought on by the American Revolution. Throughout most of the eighteenth century, Williams argued, the profits from slavery and the slave trade proved crucial to financing the early stage of the British Industrial Revolution. But when Americans secured their independence, they broke free from Britain’s imperial trade restrictions, undermining their efficacy. British capitalists quickly became converts to free trade and began denouncing the West Indian “monopoly” for using mercantilist protections to keep the slave economies artificially afloat. In Williams’s telling, the capitalists turned against slavery out of cupidity rather than humanity.

This two-part story has come to be known as the Williams thesis, and although it has provoked decades of debate it has largely survived, albeit in somewhat modified form. Most scholars now agree that slavery and the slave trade were integral, though not necessarily indispensable, to British economic development in the eighteenth century. And most agree that the world’s first abolitionist movement emerged in both the US and Britain as a consequence of the American Revolution, especially in the 1780s, though not necessarily because capitalists began assailing slavery.

What the Williams thesis could not explain was the dramatic revival of slave economies in the first half of the nineteenth century. No doubt something changed in the late eighteenth century, but it was not simply a case of capitalists suddenly turning against slavery. Rather, as Leonardo Marques points out in his exceptional survey of US efforts to suppress the slave trade, the Age of Revolution created a contradictory world that simultaneously encouraged and abolished slavery.1

On the one hand, the American Revolution dealt a severe blow to slavery in the United States. One state after another abolished slave trading, and in the 1790s the US became the first nation to begin actively suppressing it. In the northern states slavery itself was being abolished, some of the first abolitions in world history. From these would emerge a politically active community of free Blacks who went on to become leaders in the antislavery movement. At the same time, the new nation committed itself to restricting slavery’s expansion, setting the stage for the eventual admission of five more free states into the Union. Call this the invention of “the North.” But slavery in the plantation states in the South was also shaken by the Revolution. During the War of Independence tens of thousands of slaves escaped to the British, never to be returned to slavery. Tobacco and indigo plantations suffered devastating declines that in turn prompted a wave of manumissions, and with it the creation of free Black communities in the upper South.

Those emancipatory tendencies were soon checked, in part by forces unleashed by the Revolution itself. The rapid economic development of Britain and the United States produced an explosion of consumer demand for the products of slave labor, notably sugar, coffee, cocoa, and above all cotton, which resulted in an increased demand for African slaves. Thus the decades after the American Revolution witnessed human history’s first sustained efforts to destroy slavery, beginning in the northern United States and Haiti, and at the same time the dramatic revival of slavery—a “second slavery”—in Brazil, Cuba, Puerto Rico, and the southern United States.

All attempts to shut down the Atlantic slave trade operated within this contradiction. The history of the slave trade in the United States is, then, a story of significant moves to suppress it in the face of determined efforts to evade the laws against it. Harris’s book nicely illuminates both of these tendencies. The slave trade, he notes, “became indelibly marked by efforts to stop it.”


In 1794 and again in 1800 Congress made it a crime for American crews or ships to participate in the foreign slave trade. The US banned all slave imports in 1808, and between 1818 and 1820 the US defined slave trading as piracy, subject to the death penalty. Thereafter violations were rare, and few enslaved Africans were smuggled into the United States.

But that did not end US participation in the slave trade. The American shipbuilding industry was becoming the envy of the world, and vessels built in US shipyards—the famed Baltimore clippers, for example—came to dominate Atlantic trade, including the illicit slave trade. And there were always Americans willing to break the law by serving as captains and crew on illegal slaving voyages.

In the commerce between the US, Africa, and the slave plantations of Brazil and the Caribbean, two of the three legs of the triangle were technically legal. American crews and ships could trade freely with West Central Africa, or with Brazil, for example. But once the Americans reached their destinations, they could sell both their cargo and their ships to local slave traders who completed the third, illegal leg of the triangle—transporting enslaved Africans to the Americas—under foreign auspices. Some American diplomats and consuls fumed at the brazen evasion of American law, while others turned a blind eye. Part of the problem was that closing down the slave trade was never the main priority of US officials, which was to safeguard the legal commerce of American citizens.

Still, the screws on the slave trade were steadily tightening. The French began suppressing it in earnest in the 1830s. In 1842 the Webster-Ashburton Treaty with Britain required the US to beef up its Africa Squadron to more credibly combat illegal American trading. A few years later the Portuguese stepped up their efforts to suppress slave trading in West Central Africa, as did the British. In 1850, in part due to pressure from the British navy, Brazil finally took effective measures to end its own slave trade. Leading Brazilian and Portuguese traders fled to Cuba, but in 1854 the reformist Pezuela hounded them off the island, and they fled again, this time to New York City.

The dozen or so Brazilian and Portuguese traffickers in Lower Manhattan, known as the Portuguese Company, relied on the distinct advantages of their different partners. Cuban planters were avid buyers of enslaved Africans and had the means to finance the ventures. They also enjoyed political connections that protected them from local authorities during episodic crackdowns. The Cubans in turn relied on the Brazilians as investors but also for their extensive connections to slave traders in West Central Africa. The traders living in West Central Africa were likewise essential, not only as the suppliers of slaves but as owners of the “cargo” who were liable for the greatest losses if a voyage somehow failed. And by the late 1850s a substantial percentage of them did fail, thanks in large part to the increasingly intense efforts to suppress the trade.

In New York the Portuguese disguised their ownership of ships such as the Julia Moulton by working through American intermediaries, paying US citizens to make “straw” purchases of ships and supplies, and hiring “dummy” US captains who could legally sail the ships under the American flag. By then the busiest port in the hemisphere, New York was home to merchants with trading partners everywhere, including Cuba and West Central Africa. It was also a place where Spanish gold could be laundered through reputable financial institutions and reinvested in nominally American ships engaged in seemingly legal commerce.

Despite the illegality of the slave trade, the authorities responsible for policing it faced a number of obstacles. Harris believes that suppression was hindered by the US’s unwillingness to sign a treaty with Britain that would allow its navy to intercept slave ships flying the American flag, on the grounds that it would be, in the words of a former American naval officer, “contrary to national honor and national interests.” But the record of such treaties was hardly encouraging. The slave trade to Cuba and Brazil flourished despite the suppression treaties signed by Spain, Portugal, and Brazil, whereas the slave trade to the US was effectively shut down without any such treaty. Before the 1850s most illicit slave ships flew under Spanish, Portuguese, or Brazilian flags, notwithstanding the treaties allowing the British to board such vessels.

The increasing use of the US flag in the Cuban slave trade of the late 1850s forced the British to rely on a network of spies to expose the true ownership of vessels traveling with bogus American papers. If they could not legally board US ships, the British could at least provide the US Navy with documentation of illicit slave trading. One such spy was Emilio Sanchez, a Cuban-born commission merchant in New York who combined deep knowledge of the shipping business in the city with reliable family connections in Cuba. Sanchez was both ingenious and discreet. Well known in Lower Manhattan’s merchant community, he gathered information by scouring the commercial press with a knowing eye and by striking up casual conversations with acquaintances. He used a cipher to pass along information to Edward Archibald, the British consul in New York. Between 1859 and 1862 Sanchez provided the British with information on 77 percent of the slave voyages in the Atlantic basin.

Despite the efforts of savvy spies and persistent prosecutors, shutting down the trade proved difficult. One problem was that US statutes did not have “equipment clauses” that would have made it easier to convict traders on the basis of evidence that vessels were being fitted out for slave trading. Because US law criminalized slave trading by Americans, indicted immigrants often claimed they had not been naturalized. Some even pretended in court that they could not speak English. Ships of convicted slavers were sold rather than destroyed and were often repurchased by the very slavers from whom they had been confiscated. As a result, as Warren Howard demonstrated long ago, the majority of the slave traders who were prosecuted were never punished.2

Politics also intruded. A succession of Democratic administrations made minimal efforts to enforce America’s treaty obligations. In the 1850s proslavery expansionists argued that the only way to suppress the slave trade was to wrest the island of Cuba from Spain. What good could the US do, Democrats asked (quite disingenuously), so long as Cuba was ruled by a reactionary monarchy that tolerated the barbaric trade? The effect, Harris believes, was to undermine the will to prosecute traders or enforce suppression treaties.

The more potent political challenge came from the antislavery Republican Party. Politicians like New York senator William Seward assailed Democrats for trying to shift the blame to Spain when the real problem was that a “Slave Power,” operating through the Democratic Party, controlled all three branches of the federal government. Seward and other Republicans introduced bills that would strengthen the hands of prosecutors, but they routinely failed in the Democratic-controlled Congress. In numerous speeches beginning in 1854 Abraham Lincoln called for more aggressive federal suppression of the slave trade, as did the 1860 Republican Party platform.

Under increasing pressure from Republicans, Democratic president James Buchanan beefed up US naval patrols off the African coast and in the Caribbean, resulting in the capture of twenty slaving vessels in 1859–1860. But those were also the peak years of the Portuguese Company’s activity, so although more slavers were captured, more than ever got through.

All that changed in 1861 when Republicans took the White House and control of both houses of Congress. Soon after Lincoln became president, his administration negotiated a suppression treaty with Great Britain that was easily ratified by the Senate in early 1862. At least as important was the administration’s aggressive prosecution of slave traders, focusing in particular on New York City. The most conspicuous result was the conviction of Nathaniel Gordon, a ship captain who had been illegally trading in slaves for more than a decade. Despite an 1820 statute prescribing the death penalty for such crimes, no slave trader had ever been sentenced to die. Gordon’s prosecution had been initiated under the Buchanan administration, but Lincoln, determined to make an example of him, resisted all entreaties to spare Gordon’s life. The effect was immediate. His execution in 1862 sent members of the Portuguese Company scurrying to close down their business and flee the country. US participation in the slave trade was effectively shut down.

For a few years Cuban traders, with Spain’s support, continued to traffic in enslaved Africans. But the combined pressure from Britain and the US left Spain and Cuba increasingly isolated. Conservative reformers in Cuba, hoping to resist foreign intervention and protect slavery itself, began to suppress the illegal slave trade in earnest. Finally, liberal reformers in Spain withdrew their country’s support, and thus the 350-year-old Atlantic slave trade came to an end.

The tale told in The Last Slave Ships could easily seem like a relatively minor footnote to the much older and much larger history of the Atlantic slave trade. A handful of renegade slave traders, on the run from Brazil and Cuba, managed to revive their business in New York for a few short years before being run out of yet another town. “The midcentury trade,” Harris acknowledges, “had always been in some ways fragile.” But what makes his book so valuable is his ability to use this last dark era of the slave trade as a window onto a much wider world of international diplomacy, imperial arrogance, criminal conspiracy, financial shenanigans, and political conflict.

It is this last point that deserves particular attention. Harris is that rare historian who revels in complexity and contradiction and yet manages to also write a clear and gripping narrative. There are obvious villains in this story, but the heroes are never entirely heroic. Without doubt the British used their considerable diplomatic and military muscle to lead the world in the suppression of the slave trade. But at the same time, Harris notes, “the British themselves aided the traffic indirectly by selling slave trading goods on the African coast and by importing vast amounts of Cuban sugar.”

The same could be said of the United States. Its textile manufacturers and consumers constituted a seemingly insatiable market for the products of slave labor, and its government committed itself to a system of free trade. Together, these two great forces of capitalist development created powerful incentives to keep alive the commerce in enslaved Africans. And yet the United States was also the first nation in history to pass legislation designed to suppress the slave trade and, in the face of a rapidly expanding cotton economy, the federal government effectively shut down the importation of slaves by 1820. “The United States,” Harris aptly concludes, “proved to be critical to both the slave trade and its eventual suppression.”

One other conclusion seems unavoidable. The slave trade did not die on its own; it had to be killed. It took sustained political opposition to overcome the powerful economic incentives that kept the slavers in business. The same could be said of slavery itself.