That Most Precious Merchandise: The Mediterranean Trade in Black Sea Slaves, 1260-1500

Hannah Barker’s book is a thorough and engaging evaluation of late medieval slave trading practices in the Mediterranean. The tile is taken from the 15th-century recollection and denunciation of an Alexandrian slave market by Felix Fabri, a German friar (p. 209). His disgust at the sale of people, that most precious merchandise whose salvation Christ had purchased with his death, serves as a stark reminder that slave trading was alive and well amongst Mediterranean societies of the late Middle Ages. Drawing from an extensive source base of both Latin and Arabic texts, Barker’s study seeks to demonstrate the existence of a ‘common culture of slavery’ (p. 3) amongst its main participants: the Venetians, the Genoese, and the Mamluk sultanate. The result is an impressive survey of slavery in the eastern Mediterranean from the initial grant of Black Sea trading privileges to these groups in the second half of the 13th century to the commercial shifts caused by Ottoman conquest in the late-15th century.

Consisting of seven chapters, the book is grouped into two thematic parts. The first examines the practices which constituted a ‘common culture of slavery’, including the uses of slaves in Italy and Egypt, justification for enslavement, and the processes of sale. The second seeks to understand the external forces and ideas which impacted these slaving mechanisms, specifically the effect of Black Sea politics on access to the slave supply, direct political and commercial constraints upon traders and trade routes, and the embargo of slave exports to the Mamluk sultanate advocated by crusade strategists. Numerous graphs and tables are welcome inclusions and clearly illustrate Barker’s inferences from the archival data. Maps placed at the beginning of the book illustrate the trade routes sketched out verbally in Chapters 5 and 6.

The introduction provides a necessary contextualization of the Black Sea trade within wider Mediterranean slaving networks and addresses the wide range of source material available in Latin and Arabic. Importantly, it rejects the two main strands of historiographical hypotheses which have dominated, in some cases stifled, studies of medieval slavery for over a century: the Marxist economic perspective and the theory of religious amelioration. Barker’s integrative approach to Italian and Egyptian slavery provides a new and significant critique of both concepts. The Marxist theory of slavery is Eurocentric and difficult to apply in a Mamluk context which yields few surviving economic sources. Insistence upon religious amelioration by either Christians or Muslims is unhelpful in a cohesive slaving system which relied upon the cruelties and violence of enslavement, transport, and sale perpetrated by both groups simultaneously.

The first chapter furthers this critique by laying out late medieval Mediterranean assumptions about slavery: that it was a ubiquitous and legitimate form of property ownership, that slaves’ origins were rooted in religious identity, and that anyone could become a slave. Following an overview of Latin and Arabic terminology, the author turns to philosophical justifications for slavery in Christendom and the Islamic world, as well as the legal limitations of slave status. In theory, slaves were expected to be of a different religion than their new owner and to then convert to the owner’s religion. This was not always true in practice, and distinctions were drawn between different groups within the same religion (for example, Catholics versus Greek Orthodox Christians and Christians from the Caucasus) which allowed for more indiscriminate enslavement of coreligionists. Consequences of this practice were individual legal challenges brought by the enslaved and bigger political controversies. Mamluks likewise wilfully ignored the religious identity of many Tatars and Alans, leading to the enslavement of Muslims by Muslims. In both Italy and Egypt, authorities ‘were more concerned with protecting souls from apostasy than bodies from slavery’ (p. 38); the enslavement of coreligionists meant that they could not be enslaved and converted by the ‘wrong’ side. Any free person could be captured or enslaved through war or piracy, and ransom did not always guarantee an escape from servitude.

Chapter 2 problematizes other contemporary categories associated with slave status, namely language and race. Barker illustrates that these terms for describing and identifying slaves did not form the ideological basis of slavery in the Black Sea slave trade. Instead, language and race served as practical descriptors to shore up or supplement religious identity, which itself could be either more difficult to prove or more easily contested in court. Slaves could be categorized by their own spoken language, as well as by the language imposed upon them, particularly in naming conventions. Race in the late medieval Mediterranean was perceived as a spectrum, and slaves were categorized by numerous physical and mental stereotypes linked to geographic origin and ethnicity. The colouring recorded by slavers was linked to health rather than skin colour, a reflection of the individual slave’s humouric balance. Coloration could in turn be linked to stereotypes regarding a slave’s temperament, particularly in the Islamic world, but coloration was not used as a category of race in and of itself and remained only one of many recorded physical descriptors. Race was sometimes linked to an individual’s ‘enslaveability’, but these perceived connections were not universal and, like language, remained secondary to religious identity.

Moving from the ideological and practical identification of ‘enslaveable’ people, Chapter 3 turns to discussion of the slave populations in Venice, Genoa, and the Mamluk sultanate. Initially focusing on demography, location-specific source materials such as Venetian wills and Genoese tax farm records provide hints as to population size. The largest quantity of data survives from Genoa, for which Barker estimates slaves at 1-2% of the population in the 13th century, rising to 4-5% in the fifteenth. Given the patchier coverage of sources from Venice and the sultanate, the author cautiously refrains from providing population estimates there, instead indicating household numbers where they emerge and emphasizing the size and variability of slave numbers in Mamluk households. These estimates may not go as far as some would like (for instance, there is no discussion of whether the total Venetian slave population may have been similar to that of Genoa or experienced parallel fluctuations), but they demonstrate Barker’s careful analysis of disparate source material. Breaking down population data by age and gender indicates the importance of a slave’s youth in their desirability, as well as the demand for girls and boys in both Italy and Egypt. Further discussion highlights the role of enslaved men, women, and eunuchs in each society. Slaves were predominantly used as domestic servants whose tasks could be shaped by racial stereotypes. Key distinctions appear in the position of mamluks – slave soldiers – and eunuchs in the sultanate, the sexual exploitation of women in all three societies, and the difference in the status of children from slave-free unions in Christian and Islamic legal contexts. Barker also includes an examination of the social status, even mobility, available to slaves through their owners, contrasted by variation in the treatment of slaves and their potential for resistance.

The following chapter focuses on the mechanisms of the slave trade, outlining the location of sales and the appearance of slave markets, the brokers who negotiated the trade, the physical inspection of slaves as merchandise, the negotiation of a price, and the creation of a sale contract. By plotting price data for each society, Barker is able to illustrate individual trends corresponding to year, age of the slave, gender, race, and colour. Despite the wide variation in sources for this information between societies, this chapter does much to illustrate the integration and interconnection of Italian and Egyptian slaving practices.

Chapter 5 examines access to the supply of slaves in the Black Sea in order to interrogate this slaving system as - in Joseph C. Miller’s terms - social, political, and economic strategy (p. 121). The first half of the chapter surveys the mechanisms and targets of enslavement, with case studies of child sale and raiding. Warfare around the Black Sea and farther afield created captives, whom soldiers and warriors could either ransom or sell to slavers in the Genoese colony of Caffa and the Mongol port of Tana (which housed a Venetian community). Kidnapping and piracy also contributed to the pool of slaves. Regarding the sale of one’s own children, medieval records point to motivations ranging from poverty, greed, and barbarism, to the ambitious pursuit of a career as a mamluk for boys. The second half of the chapter addresses the political and economic factors at play in the control of Black Sea slaving during periods of conflict or alliance and how this translated to commercial power or instability for the Genoese, Venetians, and Mamluks. Working backwards from Mediterranean sources such as notarial registers in the absence of surviving Black Sea material allows Barker to examine the impact of political events on slave trading. This includes demographic changes in exported slaves, such as the influx of Tatar slaves resulting from civil war in the Golden Horde in the 1360s and 70s and a later shift towards Circassian slaves.

Where Chapter 5 addressed the more indirect impacts of politics and conflict on slave supply, Chapter 6 examines the political, geographic, and economic constraints imposed upon slave trading. It ultimately demonstrates that medieval states had no moral opposition to slave trading and instead sought only to regulate it and profit from it. Estimates of scale are provided based on Italian tax records and sultans’ mamluk purchases. Shifting sea and land trade routes and shipping capacity over the 240 years covered are reconstructed with reference to physical geography and political restrictions. Genoese and Venetian domination of shipping routes led to their administrative regulation of slave trading in the form of taxes and laws. Mamluk sultans had less control but offered incentives to traders such as tax exemptions and the purchasing of slaves at above-market values to attract merchants. There were few specialized slave traders; merchants usually carried slaves as one of numerous commodities, and often merchants purchased slaves for themselves or as agents rather than for resale. In the case of Mamluk traders, slave trading could also be combined with diplomacy in missions to the Golden Horde. Shipping slaves accrued the same overheads as other goods, including insurance, freight charges, and taxes.

The final chapter examines the impact of crusading ideology on the interaction between Christian and Muslim states tied together by a slave trading system. The Italian states and the Mamluk sultanate clashed over the trade in mamluks, whose sale to Muslim buyers represented a loss to Christendom for the former and a strengthening of Islam for the latter. This ideological conflict was sharpened by the Christian-held belief that most, if not all, mamluks were converts to Islam from Christianity, which in turn led to the belief that the sultanate was full of crypto-Christians who would one day denounce their Muslim lords. This even extended to the Mamluk sultans whose careers originated in the ranks of enslaved mamluk soldiers. The popularization of crusade strategy handbooks following the fall of Acre in 1291 meant that an embargo of mamluk and other slave importation to Egypt was regularly repeated as a means of reducing the sultanate’s military might and stemming the perceived flow of souls out of Christendom. Calls for embargo also extended to military supplies and any goods which could result in customs revenue for the sultanate. These texts therefore laid blame for the trade’s continuation on ‘bad Christians’. Barker’s assessment of merchants in Chapter 5 from the perspective of numerous source genres clearly demonstrates this to be an inaccurate reflection of Christian states’ attitudes toward the slave trade. Comparison to the practicalities of crusade strategy in the 14th and 15th centuries indicates that slave trading between the Italian states and Egypt was part of a complex network of political and economic connections. The enforcement of embargo was not always in the interest of Venetian and Genoese rulers, and ultimately only Genoa’s control over slave supply via Caffa offered real power over Mamluk trade links.

Despite significant differences in the uses of slaves and control over trade routes, Barker shows that slave trading brought together the Venetians, Genoese, and Mamluks through complex political and commercial networks and ideological justifications for slavery. The author concludes that this represents a common culture of slavery. One concern with this conclusion is the extent to which this situation represents a specifically late medieval Mediterranean culture rather than the broad attributes common to many historic iterations of slavery. A number of the similarities Barker points to - religious justifications, the universal threat of enslavement, nonspecialized traders, the sale of slaves in both public and private spaces – are by no means unique to this region or this time period, even when all are taken together. In acknowledging the differences between Italian and Egyptian slavery, Barker points to striking features which contradict ideas of common culture, such as the reliance on eunuchs and slave soldiers in the Mamluk sultanate, disparate local attitudes towards the people who sold slaves, and significant variations in who owned slaves and how many (the difference between tens of thousands of slaves owned by individual sultans and amirs versus the handful owned by even the most wealthy Italians, for example). 

Barker’s arguments for commonality are instead strongest when focused on depicting Venetian, Genoese, and Mamluk merchants and buyers as operating within a single, interconnected slaving system. This system was developed and continually reshaped to suit unique regional practices and medieval ideologies, creating a constant push and pull between Italian and Mamluk societies. While it is ultimately a semantic complaint, I am not certain that this amounts to a common culture which can be distinguished from the shared features of many slaveholding societies, but as a system it certainly can. Barker’s emphasis on common participation within this system by groups who are typically examined separately and in isolation nevertheless confirms the importance of her study for our understanding of late medieval slave trading.

Barker’s analysis is careful and methodical, even cautious, throughout. She does not fall into the same traps that other historians of medieval slavery have, such as maximal slave population estimates made from problematic evidence or assumptions regarding the extent to which religious ideology of slave trading held in practice. In addition to a wide variety of medieval sources, including extensive archival documents, Barker deploys essential sociological and anthropological works on slavery by authors such as Orlando Patterson, David Brion Davis, Joseph C. Miller, and Claude Meillassoux to interrogate this late medieval context. Barker’s resultant conclusions, particularly regarding religious identity and race, are important additions to our understanding of historic justifications of slavery and its inherent contradictions. 

The strict delineation of this study’s parameters owing to practical constraints such as time and language (p. 5) creates an intensive study of Black Sea and Mediterranean slave trading from the point of supply to the point of sale, from the view of the three major participants. This leaves numerous questions and directions for further research. How did this slaving network interact with or compare to other contemporary Mediterranean and trans-Saharan slaving networks? And how did this look especially in the late-15th century, during what we now see as the origin of the transatlantic slave trade? What can be said about the enslavement practices and trade networks in Eastern Europe and Central Asia that funnelled slaves to the Black Sea in response to Mediterranean demand? To put it simply, what are the greater chronological, geographical, and economic contexts and how do they impact our understanding of either medieval connections or historical slavery?

While this book does not aim to provide a comprehensive picture of Mediterranean slave trading or of the slaving networks which moved slaves to the Black Sea, it gives a new and extensive assessment of the ideologies and practices which contributed substantially to these respective phenomena. It is a case study of great importance. Barker’s wielding of diverse sources emphasizes similarities and divergences within a common trade system which connected Christian and Islamic states politically and economically. This monograph is undoubtably a significant and detailed contribution to our understanding of medieval slavery and of medieval economies.

The author is happy to accept this review and does not wish to comment further.