This paper aims to discuss the process of delegitimisation of Brazilian slavery in the second half of the nineteenth century. Several reasons contributed to delegitimise the slave regime in Brazil, such as the end of the Atlantic slave trade, the rise of the average price of a slave and the growing number of manumissions. A large number of these manumissions were obtained through freedom suits, in which slaves brought lawsuits against their masters arguing in the courts that they had the right to be freed. The paper focuses specifically on the freedom suits initiated in the late 1860s on the border of Brazil with Uruguay. In these lawsuits, slaves argued that, because they had crossed the border and stepped on free Uruguayan soil, they had the right to be freed once they returned to Brazil. Lawyers based their petitions on an 1831 law that prohibited the entrance of slaves into Brazilian territory. It also demonstrates that the free soil concept, after being considered juridically legitimate by the courts, was used by abolitionist lawyers throughout the country in the 1870s, contributing to the political movement that ended the slave regime in Brazil. [ABSTRACT FROM AUTHOR]