On the Water

Forced Crossings

The Atlantic slave trade was the largest forced migration of people by sea in history.

Hard labor made tobacco, rice, and sugar plantations profitable. Buying and enslaving the people who supplied this labor ultimately became a lucrative and tragic part of the commerce in the Atlantic world’s maritime web of connections. During nearly 400 years of Atlantic-centered trade, between 11 and 15 million Africans arrived in the Americas as slaves. While the actual numbers are not known, scholars speculate around 1 million people were brought to North America.

The Middle Passage

Crossing the Atlantic in the hold of a slave ship, or slaver, was a horrific ordeal. Perhaps one third of the captives perished on this journey, known as the Middle Passage—the middle leg of a three-part trade in slaves and goods between Europe, Africa, and the Americas.

Sailors packed people together below decks. Standing was impossible, and even rolling over was often difficult. Poor ventilation, dampness, heat, cold, seasickness, rats, poor food, and a lack of sanitation left the conditions squalid, suffocating, and deadly. Outbreaks of disease spread quickly among captives and crew.

From Thomas Astley, A New and General Collection of Voyages, 1746

Courtesy of the Library of Congress

Slave factories on the Gulf of Guinea (modern Nigeria)

Captive Africans were marched great distances overland to Africa’s western coast. There they waited weeks or months in “slave factories” for the ships that would carry them to plantations in the New World.

Courtesy of the American Antiquarian Society

“To be sold,” 1769

For almost four centuries, the demand for labor on the plantations of the New World fueled a vast transatlantic market for the enslavement of people from Africa. This broadside advertised the sale of people from Gambia at Charleston, South Carolina.

Map by Willem Janszoon Blaeu.

Courtesy of the Historic Maps Division, Department of Rare Books and Special Collections, Princeton University Library

Map of Africa, 1644

This map includes European names for parts of the West African coast where people were captured and held for the slave trade.

Lent by the National Museum of Natural History

Manilla from Nigeria

Slaves were valuable, and African traders demanded foreign goods for the captives they sold. Europeans bartered for slaves with copper or bronze bracelets called manillas, like this one, which was cast in Birmingham, England. Manillas were used as currency in West Africa.

Lent by the National Museum of African American History and Culture


These ankle shackles are of the type used to restrain enslaved people aboard ships in the Middle Passage.

Slave Ship

This model shows a typical ship in the early 1700s on the Middle Passage. To preserve their profits, captains and sailors tried to limit the deaths of slaves from disease, suicide, and revolts. In the grisly arithmetic of the slave trade, captains usually chose between two options: pack in as many slaves as possible and hope that most survive, or put fewer aboard, improve the conditions between decks, and hope to lose fewer to disease.

Reproduced from a watercolor by Lt. Francis Meynell

Courtesy of the National Maritime Museum, Greenwich

The slave deck of the Albanez, 1845

Great Britain abolished its slave trade in 1807 and used its naval power to discourage other nations from the trade. In 1845 a British sailor painted this image of enslaved Africans below decks of the Brazilian slave ship Albanez (or Albaroz). The British sloop Albatross captured the slaver with 300 Africans aboard in March of that year.

Resistance and Revolt

Enslaved people on the Middle Passage were not simply passive captives. Some refused to eat and had to be fed against their will. Others threw themselves overboard rather than submit to slavery. This image shows a rare revolt aboard a slave ship. The ship’s officers are crowded behind the barricade while the captives fill the deck, some diving into the sea.

Plate, from Carl Bernhard Wadstrom’s An Essay on Colonization: Particularly Applied to the Western Coast of Africa, 1794–1795

Courtesy of the Library Company of Philadelphia

African Culture and the Middle Passage

These 19th-century objects came from areas of Africa that were homelands to millions of people sold into slavery. They express their makers’ sense of beauty, utility, and sacredness. The objects remained in Africa, but the ideas underlying these figures, tools, and instruments—what they meant and the cultures they represented—made it across the Atlantic with their creators.

Lent by the National Museum of Natural History

Eshu figure, Yoruba people, Nigeria

Rice hoe, Diola people, Senegal

Memory board, (Lukasa), Luba (Congo)

Thumb piano, Angola

Palm oil pot, Liberia

Courtesy of the Library of Congress

The slave decks of the ship Brooks, 1788

This famous plan has appeared in almost every study of the Middle Passage published since 1788. Working from measurements of a Liverpool slave ship, a British parliamentary committee filled the drawing’s decks with figures representing men, women, and children. The drawing shows about 450 people; the Brooks carried 609 on a voyage in 1786.

Courtesy of the National Portrait Gallery, Smithsonian Institution

A Middle Passage Narrative

Olaudah Equiano wrote an account of the Middle Passage in his 1789 autobiography. A portion of his story can be heard at the audio station in the “Web of Connections” area on the other side of the gallery.

Recent scholarship has called into question Equiano’s place of birth and whether his narrative is a firsthand account. Whether born in Africa or Carolina, many scholars agree that the basic content of Equiano’s narrative is a significant document that rings true.

The End of the Slave Trade

Courtesy of the Library of Congress

In the early 1800s, opposition to slavery grew on both sides of the Atlantic. A few nations joined in declaring the transatlantic slave trade illegal, yet most countries took years to abolish slavery within their borders. The United States banned the importing of African slaves in 1808, but slavery remained legal until the passage of the 13th Amendment in 1865.

Commemorative medals, 1807 and 1834

Great Britain abolished slave trading in 1807 and gradually ended slavery throughout its empire in the 1830s. It used its naval power in the 1800s to discourage other nations from slave trading. These tokens commemorate these events.

British abolitionist one-penny tokens, 1834

These tokens ask, “Am I not a man and a brother” and “Am I not a woman and a sister?” Reformers in Britain and America pressed for an end to slavery as cruel and immoral. Tokens like these, designed to spread the reformers’ message, were common on both sides of the Atlantic from the 1790s into the 1860s.