The last decade has witnessed a significant re-evaluation of the influence of Africans and their descendants on the Río de la Plata region. During recent bicentennial commemorations of national independence, activists and researchers alike have addressed the present-day challenges faced by black populations and have shed new light on their history. In so doing they have contested prevailing national myths that have long marginalised peoples of African ancestry. From Shipmates to Soldiers advances these discussions in fundamental ways by exploring the process of identity formation among slaves and free blacks in late colonial and early republican Río de la Plata. By assembling a remarkable range of sources and creatively teasing out evidence of black participation in religious, military and cultural organisations, Alex Borucki reveals the quotidian struggles of Afro-Rioplatenses to shape their own lives. Borucki has written path-breaking studies on nineteenth-century slavery and abolition in Uruguay, but in his English-language debut, he widens the temporal scope and considers populations on both sides of the estuary (primarily in the cities of Montevideo and Buenos Aires). Moreover, From Shipmates to Soldiers situates this region within the research on slavery and freedom throughout the Americas, and accordingly, this excellent study deserves to find an audience among Río de la Plata specialists and scholars of Afro-Latin America more broadly.

The book begins by analysing the growth of the region's black population within an Atlantic world context. Late eighteenth-century imperial reforms stoked demand for enslaved labour in the region's booming commercial outposts, which by 1810 led to Africans and their descendants becoming around one-third of the total population of Montevideo and Buenos Aires. Borucki traces the routes of the slave trade to reveal the Río de la Plata's web of connections to Africa. He demonstrates the importance of trans-imperial networks among the Spanish and Portuguese colonies: indeed, approximately 60 per cent of Africans who disembarked in the Río de la Plata first passed through Brazilian ports like Rio de Janeiro (p. 36). By the same token, direct trade with sites across Africa ensured that the black population of the Río de la Plata had highly varied backgrounds. Equally important, through these trade routes and experiences of captivity on both sides of the Atlantic, enslaved Africans developed relationships as ‘shipmates’, which encouraged the adoption of umbrella terms such as ‘Congo’ or ‘Mina’. Borucki employs marriage records in novel ways to show how grooms and their witnesses invoked shipmate bonds before Catholic Church officials, suggestive of their broader efforts to adapt African backgrounds to New World circumstances.

The book's core addresses different facets of associational and political life. Chapter 3 profiles free and enslaved men who asserted positions of leadership within religious and military organisations. From membership rolls and other evidence, the author draws conclusions about new identities: for instance, while black militias were diverse in composition, locally-born free blacks predominated as leaders; by contrast, foreign-born individuals led local African ‘nations’ known as tambos, and Catholic confraternities operated somewhere between these poles. Subsequent chapters explore black involvement in caudillo politics and civic life, including the role of Africans and their descendants in developing the Day of Kings celebration. One of the largest festivities in early republican Montevideo, the Day of Kings generated political wrangling over the location of black ritual spaces within the urban landscape. From Shipmates to Soldiers also offers a greater appreciation of the complexity of black political engagement and patronage relations in an era of intense civil strife: in one illustrative case from 1817, a group of freedmen in Montevideo deserted from patriot armies to pro-slavery Portuguese forces, a move motivated by their desire to safeguard their own freedom and secure their place of residence. Military service placed heavy demands on Afro-Rioplatenses, but allowed black male soldiers to influence white elite politics, augment their own authority and build bonds with their peers. One of the book's highlights is its discussion of how Uruguayan newspapers depicted military sacrifice to the nation, in some cases by echoing the actual demands of black militiamen and in others by publishing texts written by white editors in Bozal, a Spanish dialect peppered with African words.

The final chapter focuses on the case of Jacinto Ventura de Molina, a black letrado who embodied many of the larger trends of this period, while also expressing a unique worldview through his writings. Born in the Spanish-Portuguese borderlands of Rio Grande do Sul to African parents, Molina lived through the transition from colonialism to republicanism in Montevideo and its environs. From Shipmates to Soldiers introduces the reader to this largely forgotten figure (Borucki has also edited a recent Spanish-language collection of Molina's writings). Although Molina was staunchly conservative and devoutly Catholic, his writings espoused what Borucki calls a ‘new and diasporic “black” consciousness’ (p. 184), one that betrayed a fondness for monarchy and colonial hierarchy, yet defended the value of Africans and the rights of the Pueblo Negro.

Given the nature of the historical sources, there are many aspects of black life in the Río de la Plata that remain opaque. The author acknowledges openly that men predominate in the ecclesiastical and state archives consulted for this study; yet, one cannot help but wonder how women experienced this tumultuous period of Atlantic slavery, colonial crisis and nation-building. In his defence, Borucki tries whenever possible to integrate the stories of individual women and the category of gender into his analysis. Likewise, the process of ‘identity formation’ is itself difficult to gauge from available records, and at times the book might have delved more into how certain bureaucratic expectations and contexts helped shape representations of racial and ethnic identity. The need for additional research on these topics should by no means detract from this book's many accomplishments, not least of which is the author's ability to connect varied geographies and spheres of everyday life. Borucki's work does not simply document the presence of Africans and their descendants; rather, it profoundly deepens our understanding of how black associations and individuals contributed to the very making of societies in the Río de la Plata.