The landmark Supreme Court case that addressed the legality of "separate but equal" was Plessy v. Ferguson, decided in 1896. This decision upheld state laws requiring racial segregation in public facilities under the doctrine that racial segregation was constitutional as long as facilities were equal in quality. The case stemmed from an incident involving Henry Louis Plessy, who was arrested for sitting in a "whites-only" train car. The ruling legitimized racial discrimination and paved the way for Jim Crow laws throughout the South, leading to systemic inequality that persisted for decades until being overturned by Brown v. Board of Education in 1954.