The Forgotten Slave Trade: Thirteen Centuries of Slavery in the Islamic World

The transatlantic slave trade occupies a prominent place in modern historical consciousness. Its cruelties are taught in schools, examined in universities, commemorated in museums and invoked in contemporary political debates about racism, colonialism and historical responsibility. Yet another enormous system of human enslavement, extending across North Africa, the Sahara, the Red Sea, the Indian Ocean and much of the Islamic world, receives comparatively little attention outside specialist historical scholarship. Beginning with the expansion of Islamic empires in the seventh century and continuing in various forms into the twentieth century, these slave-trading networks transported millions of Africans into servitude. Their history raises an uncomfortable question: why is Western involvement in slavery so extensively scrutinised while the equally important history of slavery in Muslim societies remains comparatively obscure?

The scale of the phenomenon was immense, although historians continue to disagree about precise numbers. Estimates of the number of sub-Saharan Africans transported through the trans-Saharan, Red Sea and Indian Ocean networks over many centuries commonly run into the millions, with some historical reconstructions placing the cumulative total between approximately six and seventeen million. These estimates are substantially less secure than those for the Atlantic trade, which transported approximately 12.5 million Africans from the sixteenth to the nineteenth centuries, of whom around 10.7 million survived the ocean crossing. Nevertheless, even allowing for the uncertainties surrounding the earlier trade, there is no serious doubt that slavery across the Islamic world constituted one of history's major systems of forced human migration.

Its geographical reach was extraordinary. Caravans carried enslaved Africans across the Sahara into Morocco, Algeria, Tunisia, Libya and Egypt. Other routes connected the regions surrounding Lake Chad and the upper Nile to North Africa and the Middle East. Along the eastern African coast, merchants transported captives through ports such as Kilwa, Mombasa and Zanzibar to Arabia, Persia and destinations around the Indian Ocean. Zanzibar eventually became a particularly important commercial centre, with the nineteenth-century expansion of the Omani-controlled slave economy linking plantation agriculture, ivory trading and the movement of enslaved people across considerable distances. The traffic was sustained by networks of rulers, merchants, intermediaries and raiders, including both Muslim and non-Muslim participants.

The suffering inflicted upon the victims was appalling. Captives could be seized in warfare, sold by local rulers, kidnapped during raids or transferred repeatedly through commercial networks before reaching their final destinations. Families were separated, communities devastated and entire regions exposed to recurring insecurity. Those forced across the Sahara faced extreme heat, thirst, hunger, exhaustion and disease. Others endured dangerous maritime journeys or long marches from inland settlements to coastal markets. Mortality could be severe, although sweeping claims that half of all captives died during desert crossings cannot be substantiated as a general historical rule. The absence of comprehensive records should not become an excuse for minimising the suffering, but neither should the scale of that suffering be exaggerated through statistics that cannot be adequately defended.

The purposes for which enslaved Africans were purchased varied considerably. Women and girls were often employed in domestic service and, in some circumstances, subjected to sexual exploitation and concubinage. Men were used as agricultural labourers, servants, soldiers, guards, craftsmen and administrators. Some enslaved men entered military or governmental institutions and acquired positions of considerable authority, although exceptional cases of advancement did nothing to alter the fundamental coercion upon which slavery rested. The institution permitted human beings to be bought, sold and controlled as property, irrespective of the occasional opportunities available to particular individuals.

One especially disturbing aspect of slavery in parts of the Islamic world was the demand for eunuchs. Boys and men were sometimes castrated for service in royal households, palaces and other institutions. The operations could be extraordinarily dangerous, particularly when performed under primitive conditions. Historians have documented the involvement of intermediaries and specialised markets in this traffic, although reliable figures for the total number of victims and their mortality rates are unavailable. It would be misleading to suggest that castration was the normal fate of enslaved African males. Nevertheless, the practice represents a particularly brutal chapter in the wider history of slavery and deserves far more attention than it generally receives.

Islamic law provided an elaborate framework governing slavery. Classical jurisprudence generally prohibited the enslavement of free Muslims while recognising various circumstances under which non-Muslims could be enslaved. It regulated ownership, manumission, marriage and sexual relations involving enslaved persons, and religious teachings encouraged the freeing of slaves in certain circumstances. Yet these provisions did not amount to a general prohibition of slavery itself. Concubinage was recognised within classical legal arrangements, and the institution remained embedded in the economic and social life of numerous Muslim societies for centuries. That is important: religious traditions could encourage humane treatment and emancipation while simultaneously accepting the underlying institution of human ownership.

Nor was the slave trade confined to Arabs. Ottoman Turks, Persians, North African rulers, East African merchants and numerous African political authorities participated in different aspects of the system. Some African states acquired wealth and power through warfare and the sale of captives, while other African communities suffered repeated depredations. The expression "Arab-Islamic slave trade" therefore describes a broad collection of overlapping historical networks rather than a single centrally organised enterprise. Recognising that complexity does not diminish responsibility. It establishes that slavery was sustained through cooperation among numerous political and commercial interests, often across religious and ethnic boundaries.

The demographic consequences remain controversial. Some writers, including the Senegalese author Tidiane N'Diaye, have portrayed the cumulative effects of these slave trades as a form of concealed or neglected catastrophe for African peoples. Such interpretations emphasise the removal of reproductive-age individuals, the demand for enslaved women, the castration of some males and the disruption of African communities over many generations. Other historians caution against drawing direct demographic conclusions from fragmentary records or assuming that the absence of large, readily identifiable descendant populations proves exceptionally high mortality. Enslaved people and their descendants were sometimes absorbed into local societies through marriage, conversion, emancipation and changing social classifications. The historical reality is sufficiently serious without requiring every disputed demographic theory to be accepted.

The contrast with the Atlantic world is striking. The Atlantic slave trade contributed to the emergence of large African-descended populations in the Americas, where the consequences of slavery became inseparable from later histories of racial segregation, citizenship struggles and civil-rights movements. These communities preserved and developed powerful forms of historical memory, while their descendants became important participants in political debates about reparations and national responsibility. In North Africa and the Middle East, the descendants of enslaved Africans often became incorporated into societies with different systems of racial identification, social hierarchy and historical remembrance. This difference helps explain why the two histories occupy such unequal positions in contemporary public consciousness.

The availability of historical evidence is another important consideration. European maritime commerce produced extensive shipping registers, insurance records, port documents and plantation accounts. These have enabled historians to reconstruct the Atlantic trade with a precision that is impossible for many earlier commercial networks. The trans-Saharan and Indian Ocean trades operated across a much longer period, involving numerous political authorities and regions where documentation was inconsistent, scattered or subsequently lost. Scholars have undertaken important research into these systems, but the resulting history is more difficult to communicate through a single statistical narrative. The relative obscurity of Islamic-world slavery therefore reflects genuine evidentiary difficulties as well as differences in public interest.

Yet these practical explanations do not fully resolve the question of selective historical attention. Contemporary Western political culture frequently treats slavery as an especially revealing indictment of European colonialism and the societies descended from it. In some presentations, the history becomes a morality play in which Western civilisation occupies the position of the principal historical offender. The existence of extensive slave-trading systems outside the Western world complicates that interpretation. Arab merchants, Muslim rulers, African political elites and other non-European participants cannot simply be written out of the history because their involvement makes contemporary ideological narratives less convenient.

This is not an argument for diminishing European or American responsibility. The Atlantic system was an enormous moral catastrophe, sustained through commercial interests, political power and racial ideologies that inflicted lasting damage upon millions of people. Its history warrants continuing study. But moral consistency demands that equivalent attention be given to slavery wherever it occurred. The enslavement of an African child by an Arab merchant was no less objectionable than enslavement by a European trader. The sexual exploitation of an enslaved woman in a Middle Eastern household was no less serious than comparable exploitation on an American plantation. The moral status of the victim cannot depend upon the religious or racial identity of the person exercising ownership.

The history of abolition introduces another dimension often neglected in simplified accounts. Britain played a major role in suppressing international slave trading after Parliament abolished the British slave trade in 1807 and slavery throughout most of the British Empire in 1833. British naval patrols, diplomatic negotiations and pressure upon foreign governments contributed to the gradual restriction of slave-trading networks, including those operating around the Indian Ocean and the Persian Gulf. These measures were not always consistent or free from imperial self-interest, and abolition also owed much to resistance by enslaved people, humanitarian campaigns and changing political circumstances. Nevertheless, the contribution of British abolitionism deserves recognition alongside the earlier British participation in Atlantic slavery.

The persistence of slavery in parts of the Islamic world long after its abolition in most Western countries is particularly revealing. Saudi Arabia and Yemen formally abolished slavery in 1962, while Oman followed in 1970. Mauritania formally abolished slavery in 1981 and subsequently introduced legislation criminalising the practice in 2007, with further legal measures following. Legal abolition did not necessarily eliminate entrenched forms of hereditary servitude, coercion or social discrimination. These late dates demonstrate that slavery was not simply an institution extinguished everywhere during the nineteenth-century age of European abolitionism. In some societies, its legal existence continued into living memory.

The Barbary slave trade also deserves inclusion in this wider history. For centuries, corsairs operating from North African ports captured Europeans through maritime raids and attacks on coastal settlements. Their victims included sailors, fishermen and civilians who could be sold into servitude, held for ransom or compelled to labour. The numbers involved are debated, and the Barbary system differed substantially from the African slave trades. Nevertheless, it provides another reminder that slavery cannot be understood exclusively through the familiar racial categories of the Atlantic world. Europeans, Africans, Asians and peoples of many other backgrounds experienced enslavement under different historical regimes.

A fuller account must also recognise the existence of slavery within Africa before and during the expansion of external trading networks. African rulers and merchants sometimes supplied captives to both Atlantic and Islamic-world buyers, while other African societies resisted slave raiding and suffered its consequences. Internal systems of slavery varied enormously in their organisation and severity. These facts complicate attempts to assign historical responsibility exclusively according to modern continental or racial identities. Slavery was a recurring institution across many civilisations, sustained by military conquest, economic incentives, political domination and the willingness of powerful groups to exploit vulnerable human beings.

Why, then, does the public discussion remain so uneven? One explanation is that Western educational institutions naturally devote particular attention to the historical wrongs committed by their own societies. There is nothing inherently improper about that. Americans have especially strong reasons to study American slavery, just as Australians must confront the injustices within their own national history. The difficulty arises when a legitimate concern with national responsibility becomes an account of world history that neglects comparable wrongdoing elsewhere. At that point, historical education risks becoming selective moral instruction rather than a comprehensive examination of human institutions.

There is also a responsibility upon Muslim-majority societies to examine their own historical involvement in slavery. Such examination need not become an attack upon contemporary Muslims, who bear no automatic personal guilt for the conduct of rulers and merchants centuries ago. The same principle applies to contemporary Europeans and Americans. Historical accountability is not inherited criminal responsibility. It is the willingness of societies to acknowledge uncomfortable facts, preserve evidence, study the experiences of victims and reject attempts to sanitise the past. No civilisation should be exempt from such scrutiny, and no civilisation should be singled out as uniquely depraved when the historical record demonstrates the widespread character of the institution.

The Islamic-world slave trades deserve greater attention precisely because their history enlarges our understanding of slavery as a human catastrophe. They reveal how commerce, religion, warfare, social hierarchy and political power could combine to sustain exploitation across immense geographical distances and over extraordinary periods of time. They also demonstrate the dangers of treating historical memory as a competition between contemporary political identities. The suffering of millions of Africans should not be remembered or forgotten according to whether their enslavers fit a preferred ideological narrative.

Thirteen centuries of slave trading cannot be dismissed as an obscure footnote to world history. Nor should its victims disappear from public memory because their descendants are less politically visible or because the historical evidence is harder to reconstruct. The Atlantic trade deserves the attention it receives, but the trans-Saharan, Red Sea and Indian Ocean trades deserve serious examination alongside it. A civilisation genuinely committed to historical truth should be capable of condemning slavery without geographical, religious or racial exemptions. The objective should not be to redistribute inherited guilt from one population to another, but to establish a consistent moral standard: the enslavement of human beings was an injustice wherever it occurred, whoever practised it, and whatever religious, political or economic arguments were advanced in its defence.