All together over four centuries about ten million African slaves were transported to the Americas, more than six million of them during the 18th century when prices rose steadily. Africans were most viable economically for this exploitation because of their superior resistance to diseases and willingness to work. Native Americans died in enormous numbers as a result of contact with Europeans, and Europeans themselves were three times more likely to die of disease in America than Africans. Thus a greater percentage of the crews on the ships died during the passage than the slaves in miserable conditions. More slaves were continually needed, because only half as many women were transported as men, and the raising of children was difficult.

For fifty years after 1482 over 400 kilograms of gold were sent annually from El Mina (“The Mine”) to Lisbon, Portugal. Led by Tengella and his son Koly, the Denianke Fulani fought a war against Mali between 1481 and 1514. Tengella invaded Zara but was defeated and killed about 1512 by the Songhay; Tengella had led the Fulani into Futa Toro and Jolof. Mali retained authority from Gambia to Casamance, and the mansa maintained diplomatic and trade relations with the Portuguese. Mansa Mahmud III in 1534 received envoys from Joao de Barros, who governed at Fort Elmina. The Portuguese transported slaves from Benin and the Kongo to Elmina to sell them to interior merchants; but Portuguese king Joao III (r. 1521-57) declared this illegal, because the slaves were becoming Muslims.

Portuguese Jews and criminals were sent to colonize the island of Sao Tomé in the Gulf of Guinea, as the slave trade was organized. In 1506 Pereira wrote that every year they were getting 3,500 slaves, plus ivory, gold, and cotton. Portuguese established sugar plantations worked by slaves on Sao Tomé, and as late as 1560 this island was exporting twice as much sugar as the Caribbean island of Española. The Portuguese took over the Cape Verde Islands in 1484 and required a license to travel to Guinea in 1514. By 1582 the Cape Verde Islands had 1600 Europeans, 400 free Africans, and 13,700 slaves. By 1600 Sao Tomé had imported 76,000 slaves as compared to 75,000 for all of Spanish America and 50,000 for Brazil. French raiders captured 300 Portuguese caravels between 1500 and 1531, and the French increased their trade on the Guinea coast. Starting in 1553, English ships began visiting and for a while were allied with the French. Captains William Towerson and George Fenner found trading difficult, because previous English privateers had raided the coast for slaves. In 1588 English queen Elizabeth granted merchants the right to trade on the Senegal and Gambia rivers. The Dutch made their first voyage to the Gold Coast in 1595, and three years later they settled at Mori, Butri, Kormantine, and Kommenda.

After tunnels collapsed near Elmina in 1622, Africans refused to go back in the mines. The next year the Portuguese went up the Ankobra River and built a fort to work a gold mine in Aowin territory. However, after an earthquake in 1636 destroyed tunnels, the Aowin people killed Portuguese, and the surviving garrison fled to Axim. In 1625 natives near Elmina repulsed an attack by 1200 Dutch troops and 150 Africans. Organization of the Dutch West India Company in 1629 for expeditions to the Gold Coast got competition two years later when the English crown chartered the Company of Adventurers of London Trading in Africa. The Dutch fortified Mori, and the English built a fort at Kormantine. The Dutch appealed to natives upset with the Portuguese and used force to take over Elmina from the Portuguese in 1637. While Portugal was preoccupied winning its independence from Spain in 1640, the Dutch captured Axim and drove the Portuguese off the Gold Coast by 1642.

In 1660 the Dutch ended their ban on exporting firearms. The English formed a new trading company of Royal Adventurers in 1662 that included the king’s brother James. Their encroachment led to a war in 1665 with the Dutch, whose Admiral de Ruyter took back the lost towns on the Gold Coast, causing the Royal Company to go out of business in 1672. However, the same year the Royal African Company was formed with the English king as a stockholder, and between 1673 and 1704 they shipped nearly 66,000 firearms and more than 9,000 barrels of powder to West Africa. Brandenburgers, Swedes, and Danes sent traders. In 1693 the African Asameni tricked a Danish garrison into giving his men guns, and they took over the fort at Christiansborg. When the Dutch mediated, Asameni gave the fort back for 1,600 pounds after having taken 7,000 pounds worth of trading goods. The next year Dutch mining of a sacred hill at Fort Vredenburg provoked a war with the Kommenda people, who gained the Fante as allies. In 1698 the British Parliament opened West African trade to anyone paying ten percent on exports and imports as a license fee; but the Royal African Company complained, because gold and slaves were exempted.

Operating from the Cape Verde Islands, the Portuguese traded for gold, ivory, hides, spices, and slaves along the Senegal and Gambia rivers, and between 1562 and 1640 they transported about 5,000 slaves per year from the southern rivers to islands and the New World. In 1621 the Dutch moved into Gorée Island. The English built Fort St. James at the mouth of the Gambia River in 1651, and the French established Saint-Louis across from the Senegal River mouth in 1659. In 1660 the leather trade peaked with 150,000 hides meeting European demand. Gorée Island was taken by the Dutch in 1629 and 1645, by the English in 1667, and by the French in 1677. The French built the Saint Joseph fort at Galam in 1700. These western-most ports were used for transporting slaves before the larger slave markets were developed in the Gulf of Guinea and Angola.

After the Mali empire declined, the Kaabu became the dominant military power in this region. Early Portuguese trade favored the coasts and broke up the Jolof confederacy. In 1660 the Hassani were fighting the Berber marabouts in Mauritania. When Amari Ngoone defeated the Buurba Jolof at Danki, he proclaimed Wolof independent and became the Damel of Kayor.

A Zawiya (religious) leader who took the title Nasir al-Din opposed the slave trade and condemned kings who killed and enslaved people. He declared a holy war (jihad) against the Hassani in 1673 and crossed the Senegal River to invade Futa Toro, Wolof, Kayor, and Jolof. Marabouts from the countryside joined his movement, defeating and killing Wolof brak Fara Kumba. Nasir al-Din set up a theocratic government using the royal puppet Yerim Kode as brak, and he imposed an Islamic tax on tribes north of the Senegal. Turmoil occurred in Kayor as the marabout Njaay Sall assassinated Mafaali Gey for not respecting the Qur’an and then proclaimed himself viceroy. In 1674 Nasir al-Din was killed in a third battle against Hassani warriors in Mauritania, and his successor ‘Uthman was killed fighting the Wolof. Three succeeding imams were also defeated, as the marabout movement declined. Because trade had been suspended by the viceroys, the French at Saint-Louis intervened for the Futa Toro, Wolof, Kayor, and Jolof kings and helped them defeat the marabouts by 1677. The war disrupted agriculture, and famine followed. Marabouts fled from Futa Toro to Bundu, where Maalik Sy founded a Muslim theocracy about 1690, taking the title Almamy.

The war chiefs strengthened their control and exploited the slave trade. Lat Sukaabe Fall (r. 1695-1720) of Kayor monopolized the sale of slaves and firearms and took over the crown of Bawol. His reforms attempted to integrate the marabouts into his political system by making them government agents. French desire to control the gum trade provoked a war in 1717 that lasted ten years in Wolof. The French supported provincial chief Malixuri in his rebellion against Wolof brak Yerim Mbanik in 1724. After mediation failed, Malixuri lost company support and was defeated. Yerim Mbanik increased his power, and his brothers Aram Bakar (r. 1733-57) and Naatago (r. 1756-66) expanded Wolof hegemony, especially over Kayor which had suffered civil war. Naatago kept raising the price of slaves, and in 1758 the English took over Saint-Louis. That year the French also abandoned Fort Saint Joseph at Galam. The English helped Kayor damel Makoddu Kumba Jaaring to recover his territory from Wolof in 1765. After Naatago died, British governor O’Hara supplied arms to Moors in order to overcome Wolof power and to take more slaves. In six months of 1775 the English took more than 8,000 slaves from Wolof alone; the price of a slave in Saint-Louis was reduced to a piece of cloth.

In Futa Toro the violent climate of the war chiefs stimulated Bubakar Sire to appeal to Morocco for troops (Ormans) in 1716, and from then on they had to pay a grain tax. Power struggles led Samba Gelaajo to seize control with help of the Gaidy Ormans in 1725; but he turned from the Moors to the French and traded slaves for weapons. Later Samba was forced into exile but used his Orman army to return in 1738. The Moors dominated Futa Toro as one ruler followed another. Finally the Torodo party, led by Sulayman Baal, won a military victory at Mboya and ended the annual grain tribute to the Moors.

Because O’Hara was taking so many slaves, in 1776 the Torodo party banned all English trade with Galam. That year Sulayman Baal died and was succeeded by ‘Abd al-Qadir ibn Hammadi, who was chosen for his religious learning to establish a theocracy. He defeated the Moors and made them pay tribute, overcoming the Denianke and distributing land to Torodo leaders. In 1786 he invaded Trarza, killing their emir Ely Kowri. ‘Abd al-Qadir implemented land reform in Futa Toro about 1790. Kayor damel Amari Ngoone Ndeela (r. 1790-1809) renounced the previous submission to Futa Toro and killed ‘Abd al-Qadir’s envoy. ‘Abd al-Qadir organized a military expedition with nearly 30,000 people to colonize Kayor; but Amari Ngoone’s scorched-earth strategy left them thirsty and weak. ‘Abd al-Qadir was taken prisoner but was magnanimously released by Amari Ngoone after he promised not to invade again. ‘Abd al-Qadir invaded Wolof in 1796 and forced the burba of Jolof and the brak of Waalo to become Muslims. However, when he intervened in Bundu and wanted to attack the Bundu-Kaarta alliance, he was deposed by the Jaggorde opposition at home. He formed an alliance with Gajaaga and Xaaso but was killed in 1807 by the Bundu and Kaarta forces.

Large slave-hunts by the powerful Kaabu stimulated Fulbe and Mande marabouts in 1725 to revolt in order to gain security. The marabouts, led by Ibrahima Sambegu, declared it a jihad and defeated the non-Muslim Jallonke cattle herders; his nephew Ibrahima Sory smashed the pagan drums of Timbo. The Futa-Jallonke led the resistance and formed an alliance with Sulimana ruler Ayina Yella (r. 1730-50). After conquering Jallonke, Susu, and Pullis, in 1747 nine Muslim chiefs combined the Fulbe and Jallonke to form the theocratic Confederation of Futa Jallon under the leadership of Sambegu, who was given the titles Karamokho Alfa and Almamy. After he died about 1751, the army commander Ibrahima Sory used the excuse of jihad and an alliance with Yella-Dansa (r. 1750-54) of Sulimana to attack Farabana in 1754 and procure slaves. After Tahabaire became king of Sulimana, they attacked Farabana again the next year. This provoked a slave revolt, and some fled to Bundu, where they fortified Koundie. When Sulimana defected from the Fulbe and Jallonke alliance in 1762, Sory was defeated at Balia by Sankaran king Konde Burama. The Jallonke withdrew their support from the Fulbe, who reacted by beheading all the Jallonke chiefs of Sulimana in Futa. Tahabaire joined Konde Burama, and they took over Timbo and burned it in 1763. Tahabaire attacked Fugumba in 1767 but was driven back; yet he pillaged Limba, taking and selling 3,500 prisoners.

Sory fought back and eventually defeated Sankaran in 1776, becoming Almamy. When the council of ‘ulama’ (clerics) in Fugumba challenged his authority, Sory went there and beheaded those who opposed him, replaced them with his supporters, and moved the council to Timbo. So many slaves were held in Futa Jallon that several slave revolts broke out. In 1785 Mandinka slaves massacred their masters and burned the stores of rice. Sory influenced Bundu and the region, ruling Futa Jallon until 1791. Six years later his son Sadu was assassinated by supporters of Karamokho’s son. The marabouts themselves had become a slave-holding class.