This chapter uses documents and methods from both traditional political history and social history to argues that the origins of the Paraguayan War (1864–1870) can be identified in tensions surrounding the abolition of slavery in Uruguay in the 1840s and the definitive ban of the Atlantic slave trade to Brazil in 1850. These tensions were at play in the disputes over the consolidation of local nation-states and are central to an understanding of the historical process that fed into the Paraguayan War. By the early 1860s they would reach a point of no return. This argument places slavery and Black agency at the center of Brazil’s nineteenth-century international relations, breaking a silence carefully constructed by statesmen and diplomats of the Brazilian Empire.

This chapter uses documents and methods from both traditional political history and social history to argues that the origins of the Paraguayan War (1864–1870) can be identified in tensions surrounding the abolition of slavery in Uruguay in the 1840s and the definitive ban of the Atlantic slave trade to Brazil in 1850. These tensions were at play in the disputes over the consolidation of local nation-states and are central to an understanding of the historical process that fed into the Paraguayan War. By the early 1860s they would reach a point of no return. This argument places slavery and Black agency at the center of Brazil’s nineteenth-century international relations, breaking a silence carefully constructed by statesmen and diplomats of the Brazilian Empire.