Bridging the Worlds of Slave Trading: A Database of some Participants in the Mozambican, Indian Ocean and Atlantic Slave Trades

Filipa Ribeiro da Silva and David Richardson


The study of the history of slavery has been transformed in the last half century by computer technologies, which have encouraged the mining of a vast range of historical sources and the creation of datasets relating to many aspects of slavery and slave trafficking. Nowhere is this more evident than in the study of transatlantic slavery, where advances in the knowledge base have been truly remarkable, provoking some scholars of other forms of slavery to refer to the ‘tyranny’ of the Atlantic. In researching transatlantic slavery historians have unquestionably benefited from the propensity of those seeking to profit from enslaved people to keep business records and from the efforts of European states and their colonial offshoots to monitor and regulate international trade relations in the age of mercantilism. The ensuing richness of sources has allowed historians to chart in exceptional detail the flows of enslaved Africans across the Atlantic after Columbus, the ships and ship-owners involved in their forced migration, and the lives of those who survived the Atlantic crossing and gave rise to Creole societies in the Americas. Indeed, in many respects we now know far more about the migration experiences of Africans forcibly removed across the Atlantic before 1867, when the transatlantic slave trade ended, than about the millions of people of European descent who migrated to the so-called New World under very different circumstances.


Bridging Oceans

Though slavery has existed throughout human history and figured very prominently in many societies before, during and after the era of transatlantic slavery, the evidential base for investigating such societies is typically thinner than that for their transatlantic counterpart. This does not mean, however, that evidence is largely unavailable or incapable of being recovered and developed, at least in some measure. There have been estimates of slave trades out of Africa other than the Atlantic slave trade, some of which antedate the latter. They include time series, voyage-based estimates of flows of African captives into the western Indian Ocean comparable to the far more voluminous voyage records for the Atlantic slave trade. These Indian Ocean voyages existed alongside slaving voyages that took African captives from Mozambique and Madagascar to the Americas, particularly in the late eighteenth and early nineteenth century. In that respect, south-east Africa helped to service two ocean-based slave trades, one centred on the Indian and the other on the Atlantic, thereby highlighting links between the two oceans in slave trading that stretched beyond their African victims to include trade goods bartered for captives. The extent to which there were overlaps in the personnel involved in the organization and management of slaving voyages in both oceans has so far escaped detailed investigation. An important finding of the database on offer here is that some individuals did bridge two oceans in the pursuit of slave trafficking in the eighteenth and nineteenth centuries. Another finding relates to the use individuals made of institutional and legal structures of their nations’ empires in Asia and the Atlantic world to develop their business.


Content of Database

The database provides information relating to individuals involved in the organization and management of the slave trade in the Mozambique region and their connections with the broader Indian and Atlantic slave trading systems. Its focus is on agents of European descent not African, but it does include some participants of probably Asian origin. The basic unit of organization of the database is the individual organizer or manager, not the slave voyage. In this respect, the database differs from the transatlantic slave voyages database (, from which it draws some information but which uses the voyage as the basic unit of investigation. The database comprises 1,708 records of individuals, with related information on their participation in the slave trade covering the period 1750 to 1897. Based primarily on data collected by José Capela during his research on the Mozambican slave trade, the database does not offer a comprehensive listing of all Europeans engaged in the Mozambican slave trade, nor can it be seen as providing a representative sample of those participating in that trade. But it does provide insights into the commercial and financial activities of those who engaged in this branch of human trafficking and their connections with other branches of the slave trade. Given Capela’s own interests, the information relates mainly to people of Portuguese descent, but, as noted above, his data also do include information on Asian participants in this trade. It is hoped that publication of this database will encourage others to expand its boundaries to include information on agents of African, American and Asian origin who operated in the slaving circuits linking Mozambique with the Indian Ocean and the Atlantic Ocean as well as the interior of South-East Africa. It is also hoped that this dataset will inspired other scholars to explore the richness of multiple Asian archives at a local, provincial and national levels, to study the slave trade of Asians by Europeans and Asians in the Indian Ocean fully defined and the Far East and ultimately the connections of these slave trade circuits with the Pacific and the West coast of the Americas. Expanding this strand of research would allow deeper and more detailed comparative studies of slave trade and slavery systems on a global perspective.


Sources of Data

The basic information on individuals included in the database is testament to the work done over the last forty years by José Capela on Portuguese records relating to the Mozambique slave trade. Without his work this database could not exist. It draws in particular on his encyclopaedic Dicionário de Negreiros em Mozambique [Dictionary of Slave Traders in Mozambique], 1750-1897 that he published in 2007 through the Centre of African Studies at the University of Porto. An earlier version of the data taken from this collection was published on the Centro de Estudos Africanos da Universidade do Porto (CEAUP) website ( Cette adresse email est protégée contre les robots des spammeurs, vous devez activer Javascript pour la voir.  ). We have sought in our database to improve the accessibility and user-friendliness of the data posted on the Porto site by designing its layout. We have also sought to increase its value by crosschecking Capela’s Mozambican data against the data in the most recently published online version of the Slave Voyages Database, edited by David Eltis and others. The latter deals specifically with voyages entering the Atlantic slave trade, but crosschecking shipmasters and ship owners in the Capela and Slave Voyages datasets sets allows us to identify individuals who had interest in both the Mozambican and Atlantic slave trades. Since some of the ships trading to Mozambique took slaves to the Americas, consultation of Slave Voyages also allowed us to identify a further 372 individuals who had interests in the Mozambican slave trade other than those identified by Capela. The records relating to these additional 372 individuals comprise some 22 per cent of the 1,708 records contained in this dataset. The information they contain comes from sources underlying Slave Voyages.


Structure of Database

The database comprises 10 fields of information, as follows:


(1) The ID code assigned to each individual


(2) The names of the individual, listed in order of surname and other names, in modern format, with all accents and other markers removed


(3) The names of individuals as given in historical documents, including variations in spelling of names where these exist in the same and including accents and other markers


(4) First recorded year of activity in the slave trade


(5) Last recorded year of activity in the slave trade


(6) Form of recorded activity in slave trade, using descriptions given in the contemporary sources


(7) Other known activities of the individual


(8) Place of known activity in Africa and the Indian Ocean


(9) Sources of information


(10) Sources of information


(11) Sources of information


(12) Sources of information


Fields of Information

The first five fields of information are self-explanatory, but some comments are necessary on fields (6) through (12). With respect to (6), it is important to note that individuals might become engaged in slaving activities in one or more of several ways. Some were involved in slaving as a business; others were officers or crew on board slave ships; others might be involved as state officials charged with overseeing or regulating slave trafficking, among other things. Some individuals were involved in more than one capacity. The database seeks to reflect the range of ways in which individuals might become involved in slaving, therefore. In doing so, it adopts the descriptions of such forms of involvement provided in contemporary sources. They include sailor, mate, pilot and ship’s master or captain, all related to the navigation of ships at sea, as well as broker, merchant, freighter, outfitter, and leaseholder, all concerned with the organisation of voyages as business enterprises. Masters and captains were sometimes involved in organising voyages, thus transcending these categories of activities. Some descriptions of tasks or activities in Portuguese such as armador, senhorio, and fretador are not readily translatable into English. The activities described by such terms typically involved specific legal rights and responsibilities that transcended possible English equivalents such as ship captain, merchant or ship owner, and where used, therefore, we have retained such descriptions while offering simultaneously what we believe to be most appropriate English equivalent of the function described. This is intended to reflect the richness of descriptions of activities surrounding the business or maritime activities of the slave trade and, at the same time, to preserve the integrity of the primary sources on which the database is founded.


Some of those involved in the business or maritime aspects of the slave trade held other positions. They included official offices or other positions and honours, sometimes in Mozambique, in other cases in the wider Portuguese empire, and in still other cases in Portugal itself. The interlinking of slaving activities with political and other functions arguably reflected the political importance of slaving to the Portuguese state and its empire and as such was integral to the networking and commercial arrangements that underpinned slaving activities. Because of their political and economic significance, information on the political offices and other positions held by those recorded as being involved in the slave trade of Mozambique was collected by Capela in the course of his research and is listed under field (7) in this database.


The centre of much of the activity covered by this database was Mozambique but those involved in slave trafficking from this region had interests in other coastal African slave supply regions. Field (8) seeks to reflect the geographical spread of slaving interests of those recorded by Capela and Slave Voyages as being involved in the Mozambique slave trade. Capela’s directory provides much of this information, with most of the rest deriving from the online Slave Voyages database. The information given relates to imputed coastal regions of African slave supply, and follows the designations of such regions identified by Capela and the Slave Voyages database. The last, in turn, largely follow those identified by Philip Curtin in his census of the Atlantic slave trade published in 1969. The regions included in field (8) are Senegambia; Sierra Leone; the Windward Coast; the Gold Coast; the Bight of Benin (or Slave Coast); the Bight of Biafra; the Gulf of Guinea islands; West central Africa; St Helena; Southeast Africa (including Mozambique and Madagascar); Other Africa; the Indian Ocean islands; and the offshore Atlantic islands.


Fields (9) through (12) provide information relating to the sources used in compiling this database. Field (9) identifies the source within Capela’s directory and Slave Voyages of the information on which this database was built. Field (10) provides further information on the sources used by Capela to compile his directory of individuals’ engagement in the Mozambican slave trade. Field (11) indicates the Voyage ID within Slave Voyages of materials from that database used to construct this expanded Mozambican database, while Field (12) lists the sources of information given under each Voyage ID. Fields (9) to (12) collectively provide therefore a complete listing of all the primary and other sources that underpin this Mozambican database. The appendices to the database provide listings of the abbreviations used in describing the sources as well as a bibliography of such sources.


Inter-relationships between the Atlantic and Indian oceans

Historians are increasingly aware of inter-relationships between the Atlantic Ocean and Indian Ocean worlds in the early modern period. Supplying enslaved captives to both the western Indian Ocean and the Americas from the late eighteenth century onwards, if not earlier, Mozambique played a central part in the emergence of these inter-relationships. The creation of this Mozambican database of slave traders is, therefore, an important step in identifying how these connections developed. Focusing on Portuguese-speaking participants, it provides information on the names, chronologies, and the range of activities, functionally and geographically, of over 1,700 individuals who engaged in slave trading from Mozambique between the mid eighteenth century and the late nineteenth century. These years encompassed the peak years of the Mozambican export slave trade. Our ability to study the lives of those who financed and organized slave shipments from Mozambique is critical to understanding how and why the Mozambican slave trade reached the heights it did after 1750. That, in turn, is a vital step in advancing understanding of how traders developed and expanded bridges between the slave trading worlds of the Atlantic and Indian oceans during and after the eighteenth century.




1 Richard B. Allen, ‘Suppressing a Nefarious Traffic: Britain and the Abolition of Slave Trading in India and the Western Indian Ocean, 1770-1830’, William and Mary Quarterly, 3rd series, 66, no. 4 (2009), 873; Gwyn Campbell, ‘The African Diaspora in Asia’, in Kiran Kamal Prasad, ed., The African Diaspora in Asia: Explorations on a Less Well Known Fact (Bangalore, 2008), 43-82.


2 David Eltis and David Richardson, Atlas of the Transatlantic Slave Trade (New Haven, 2010), 156-158; Richard B. Allen, ‘The Constant Demand of the French: The Mascarene Slave Trade and the Worlds of the Indian Ocean and the Atlantic during the Eighteenth and Nineteenth Centuries’, Journal of African History, 49 (2008), 43-72.


3 The Trans-Atlantic Slave Trade Database,


4 Philip D. Curtin, The Atlantic Slave Trade: A Census (Madison, Wisconsin, 1969).



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