Rio de Janeiro, 1833: The enforcement mechanisms for slave trade suppression

On 25 November 1833, the sails of a ship could be seen from the docks at Rio the Janeiro. Inside the ship’s hold were hundreds of enslaved men, women, and children. That was nothing out of the ordinary. Brazil had been the main destination of the transatlantic slave trade for decades and, by the end of the first half of the century, approximately 64% of the victims of the transatlantic slave trade would have disembarked at its ports. Yet that particular vessel, a barque named Maria da Gloria, would make history as a symbol of the cruelties of the slave trade and the fight for abolition.

Maria da Gloria offers a window into the procedure and the reality of the legal regime for the suppression of the slave trade. The case starts with the ship’s capture by the British Royal Navy. After spotting the ship approaching the Brazilian shore, commander William Robertson, of the sloop Snake, believed there was enough reason to suspect it of illicit traffic. After signaling for the ship to stop, some of the Snake’s crew boarded the Maria da Gloria to find 423 enslaved people on board, most of them children under 12 years old. Robertson decided to seize the vessel and bring it to Rio for trial.

While the British Navy enjoyed considerable power over the seas, Robertson and his fellow men elaborated upon sets of rules found in Instructions issued to British Navy ships acting against the slave trade. Those rules were a product of the intricate international law regime Britain sought to create as part of its endeavor to abolish the slave trade. Following the Napoleonic Wars, Britain adopted a plan of action that was based on applying rules to the transatlantic slave trade that were quite similar to those for warfare. It was customary that officers from a belligerent state had the right to visit ships suspected of contraband (illicit cargo). If enough evidence of contraband was found, officers were empowered to seize the ship and have the vessels and their cargo adjudicated by prize courts. Britain lacked a legal basis for applying that warfare regime to states formally at peace, so it pressured other parties to sign treaties to create a similar legal structure for peacetime. After European powers included an international condemnation against the slave trade in the Declaration of Vienna of 1815, Britain succeeded in establishing dozens of treaties —most of them bilateral— providing for complex mechanisms to enforce suppression of the slave trade.

The British Navy was a major force in that effort, but its mission was neither simple nor straightforward. Not all slave trade was considered illegal when the Maria da Gloria arrived in Rio in 1833. William Robertson and his men could only act against practices according to certain conditions of ratified treaties. Capture outside those conditions was illegal, and both the British state and British officers were personally liable to demurrage and indemnification for the owners of the vessels. Among the elements that the treaties provided for determining the due amount for demurrage and indemnification was the number of lives lost during the adjudication proceedings.

The Instructions (restating the rules of the treaties) followed by Robertson to visit and capture the Maria da Gloria provided that the seized ship should be brought to the nearest “mixed commission” with jurisdiction over the case. After William Robertson led the capture, Admiral Michael Seymour was responsible for that next step on behalf of the captors. Mixed commissions (Map of mixed comissions, Internet Archive) were a variant of the prize law courts which decided cases of contraband during warfare. They were not domestic courts, but rather bodies of representatives (not necessarily lawyers) of both parties of the treaty. Under the Anglo–Brazilian treaty, two mixed commissions were established, one based in Rio and another in Freetown. Under prize law, if a vessel was found to be a good prize (i.e. the capture was held to be legal), ownership over the ship and its cargo would be transferred to the capturer. A distinct characteristic of mixed commissions was that the enslaved people on board would be emancipated as well. In case the vessel was found to be a bad prize, the ship, its cargo, and the enslaved people on board were to be returned to the ship’s owner.

Yet the outcome of Maria da Gloria before the Rio commission was neither of those. Proceedings began on 2 December 1833. The Maria da Gloria had shipped from Angola a month before, bearing a Portuguese flag. The commission only had jurisdiction over Brazilian ships and citizens. Yet, in previous years, the Rio commission had been judging cases of vessels notwithstanding the fact that they were bearing Portuguese flags, affirming jurisdiction over those cases on the grounds that the vessels actually belonged to Brazilian citizens. But that was not the decree of the Rio commission in Maria da Gloria. On 20 December 1833, both Brazilian and British commissioners declared that the commission had no jurisdiction over the case, on the grounds that the barque was owned by a Portuguese citizen.

Given that finding about the nationality of the owner, the British saw a chance to bring the case to trial under another treaty, the Anglo–Portuguese treaty, with deadly consequences for the enslaved people trapped onboard. The enslaved people, having already been confined for more than seven weeks inside Maria da Gloria’s hold, once again crossed the Atlantic, this time to Freetown. But before the case was tried again, many of the enslaved onboard succumbed to the conditions of living inside the ship, suffering from diseases and malnutrition.

On 15 March 1834, the Anglo–Portuguese commission rendered its decision. The ruling was not the one that the British officers had hoped for. The commission decided to restitute the vessel to its owners; its human cargo was also to be returned. The commission’s reasoning was that the capture of the Maria da Gloria was illegal given the place where it had been carried out. Under the treaty in force between Portugal and Britain, captures south of the Equator were not allowed. Also, based on a growing list of precedents, the commission decided that, given the vessel had engaged in illegal trade, and despite its illegal capture, no demurrage or indemnities were owed to the vessel’s owner.

Four months and eighteen days had passed since the barque Maria da Gloria had departed to Brazil from the port of Loanda with 432 enslaved people onboard. Those men, women, and children lived in confinement for the three months and eighteen days after the ship’s capture. By the time of the second decision on the case, many of them had died or fallen ill. Of the survivors, 64 were too debilitated to leave Sierra Leone and 240 would be sailed back to slavery in Brazil.

The case of the barque Maria da Gloria, “a floating charnel house” (Bethell, 2009), is rightly remembered as a symbol of the atrocities of slave trade. The case was striking even in the terrible scenario of the slave trade in the first decades of the nineteenth century. It is also particularly telling of the workings of the legal regime of slave trade suppression. After crossing the Atlantic twice in brutal conditions, the enslaved people on board the ship had their fates determined on the outcome of the analysis of the ownership of ships and the legality of their capture. Maria da Gloria, a case where all possible legal options were used by the British officers, reveals how pernicious the reality of the mechanisms of slave trade suppression could be, partly as a result of its prize-law origins. Enslaved people were far from being the protagonists in the proceedings, and even further from having their rights prioritized within those enforcement mechanisms.

Enforcement mechanisms have only briefly been mentioned in most of the historiography on slave trade suppression. The few exceptions were publications detailing the role of mixed commissions (e.g. Du Bois, 1904, Bethell, 1970). More recent work has explored the anti-slave trade enforcement mechanisms as part of new approaches to humanitarianism (Klose, 2019; Ryan, 2011), British imperialism (Benton & Ford, 2016; Scanlan, 2017), anti-slavery international law (Erpelding, 2019), human rights (Martinez, 2012) and criminal international law (Haslam, 2019).

Further Reading

• Allain, Jean. ‘The Nineteenth Century Law of the Sea and the British Abolition of the Slave Trade’, British Yearbook of International Law 78, no 1 (2007) pp. 342-388.
• Benton, Lauren. Abolition and Imperial Law, 1790– 1820. The Journal of Imperial and Commonwealth History 39, no. 3 (2011): pp. 355–374.
• Benton, Lauren. Ford, Lisa. Rage for order: the British empire and the origins of international law, 1800–1850 (Cambridge: Harvard University Press, 2016).
• Bethell, Leslie. ‘The Mixed Commissions for the Suppression of the Transatlantic Slave Trade in the Nineteenth Century’. The Journal of African History 7, no. 01 (2009): pp. 79–93.
• Bethell, Leslie. The Abolition of the Brazilian Slave Trade: Britain, Brazil and the Slave Trade Question 1807-1869 (Cambridge: Cambridge University, 1970).
• Du Bois, William E. B. The Suppression of the African Slave Trade to the United States of America 1638-1870 (New York: Longmans Green and Co, 1904).
• Kern, Holger L. ‘Strategies of Legal Change: Great Britain, International Law, and the Abolition of the Transatlantic Slave Trade’. Journal of the History of International Law 6, no. 2 (2004): pp. 233–258.
• Klose, Fabian. In the Cause of Humanity: Eine Geschichte der humanitären Intervention im langen 19. Jahrhundert. (Göttingen: Vandenhoeck & Ruprecht, 2019).
• Haslam, Emily. The Slave Trade, Abolition and the Long History of International Criminal Law: The Recaptive and the Victim (New York: Routledge, 2019).
• Lloyd, Christopher. The Navy and the slave trade: The suppression of the African slave trade in the nineteenth century (New York: Routledge, 2012).
• Martinez, Jenny S. The Slave Trade and the Origins of International Human Rights Law (Oxford: Oxford University Press, 2012).
• Scanlan, Padraic X. "Freedom’s Debtors." Freedom’s Debtors (New Haven: Yale University Press, 2017).
• Ryan, Maeve. ‘The price of legitimacy in humanitarian intervention: Britain, the right of search, and the abolition of the West African slave trade, 1807-1867’ in: Humanitarian Intervention: a History (Cambridge: Cambridge University Press, 2011).

Short Biographical Note on Contributor

Adriane Sanctis de Brito holds a PhD in Law from the University of São Paulo. Her research focuses on the developments of international law in the nineteenth century, with a focus on economic exploitation, use of force and humanitarianism. She works at a Brazilian non-governmental organization analyzing the rule of law in Brazil. She was a fellow of the GHRA 2019.