In 1858, the United States Attorney General issued an opinion, Invention of a Slave, declaring inventions by African Americans, enslaved and free, unpatentable. Within a few years, legal changes that abolished the law of slavery rendered the opinion obsolete, and it became forgotten, dropped from legal memory. Combining history and Critical Race Theory, this Essay repositions the opinion as a remembered legal story and argues that law’s selective memory has carried a cost. I excavate the generations of African American activists who researched and wrote about the opinion and its backstory of an enslaved blacksmith who invented an innovative plow. Setting their storytelling in the context of post-Emancipation advocacy for the “rights of belonging,” I demonstrate the political stakes of their efforts in the relationship among inventive ability, patents, and citizenship. I reflect on my first encounters with Invention of a Slave as an obscure part of the antebellum past and on the new perspective gained from this history of remembering. I argue that these stakes persist, making this story part of the living present of race and law. I use this personal storytelling to consider the costs of legal forgetting and the possibilities of mitigation both in this case study, with implications for the patent system and our ongoing national conversation about paths to citizenship, and in the broader projects of curating law’s memory and fulfilling law’s formal promises of racial equality.