Which landmark Supreme Court case established the principle of "separate but equal"?

The principle of "separate but equal" was established in the Supreme Court case Plessy v. Ferguson in 1896. This case arose when Homer Plessy, an African American, was arrested for sitting in a "whites only" railroad car, which violated Louisiana's segregation laws. The Supreme Court held that racial segregation was constitutional as long as the separate facilities for the separate races were equal. This ruling provided a legal justification for the widespread segregation that took place in the United States for decades, particularly in the South. The "separate but equal" doctrine was not overturned until the landmark case of Brown v. Board of Education in 1954, which found that separate educational facilities are inherently unequal.