This article argues that black men and women activists from the Caribbean and South America made key contributions to the US abolitionist, civil rights and women's rights campaigns in the mid-nineteenth century. It does so by examining three case studies of Boston and New Yorkbased activists from Brazil, Haiti and Jamaica. Using diverse primary sources from across the Americas, including court transcripts, abolitionist society minutes, and newspaper correspondence, it also demonstrates how these activists created unique inter-American dialogues on slavery, emancipation, segregation, racism, and gender between black communities in the Americas. In doing so, this article challenges current Anglo-American and North Atlantic biases in the historiography of transnational black abolitionism and civil rights, and instead shifts our attention to the inter-American sphere of black activism. Lastly, it also contributes to discussions around silence in the study of black activists during this period.In October 1833, a black man took a steamboat captain to court for refusing to allow him and his sick wife to enter the whites-only cabins on a vessel travelling from New Bedford to Nantucket, Massachusetts. In the Boston Court of Common Pleas, the plaintiff's lawyers appealed to the jury to consider Captain Edward Barker's actions a 'violation of humanity'. 1The case garnered local and national attention as a pivotal moment in early campaigns against racial discrimination and segregation. According to the Boston Daily Advertiser, 'The court room was much crowded during the trial', and thousands of readers followed regular updates published in newspapers across the US Northeast. 2 The verdict must have shocked many of them. Judge Artemas Ward ruled that the plaintiff 'was to have no more or no less damages than he would have been entitled to if he had been a white man'. 3 Aside from being one of the earliest lawsuits against segregation in Massachusetts and US history, the case was also remarkable because the plaintiff, Emiliano Felipe Benício Mundrucu, was from northeast Brazil.Mundrucu v. Barker also carried global importance for Atlantic-wide campaigns against racial prejudice. Prominent politicians, lawyers, and anti-slavery activists rallied around Mundrucu who was represented by David Lee Child and US Senator for Massachusetts, Daniel Webster. British and US abolitionists, eager to point out the hypocrisies of the early US republic, took great interest in Mundrucu v. Barker. Child, a lawyer, journalist, and prominent abolitionist, used Mundrucu's story to denounce racism in the US as far worse than anywhere else in the Americas. Comparing racial discrimination across the hemisphere, Child claimed that 'In Spain and Portugal, and their colonies, and in Brazil, it scarcely exists at all.' 4 Reporting on Mundrucu's story to the British press, renowned English abolitionist and author Edward Abdy condemned Boston's 'aristocracy of the skin'. 5 In taking a stand against segregation, a black Brazilian immigrant had focused natio...