Illegal Enslavement and International Law in the Southern Borders of South America in the Eighteenth and Nineteenth Centuries

How slavery affected international relations in South America? That's the theme of my paper, which addresses the relationship between enslavement and the making of international law in the southern border of South America in the 18th and 19th centuries. It encompasses the Spanish and Portuguese Empires in the 18th century; Uruguay, Argentina and Brazil in the 19th century. Based on judicial and diplomatic sources, the paper analyzes border crossings by enslaved individuals, and the diplomatic tensions it created. It argues that the fleeing of enslaved individuals from the Portuguese to the Spanish Empire during the 18th century helped to widen the definition of the medieval concept of “free soil”, associating it to notions of freedom, territory and nationhood. In the 19th century, the same movement, along with the illegal enslavement of free blacks in Uruguay and Argentina, generated international complaints that became a key element to the development of international law – especially regarding the extradition of individuals – in 19^th-century South America.