What principle did Plessy v. Ferguson establish in 1896?

The case of Plessy v. Ferguson in 1896 established the legal principle of "separate but equal," which allowed for racial segregation in public facilities as long as the separate facilities were of equal quality. This ruling provided a constitutional justification for the segregation laws that were prevalent in many states, particularly in the South, and it upheld the notion that racial segregation did not necessarily imply the inferiority of one race to another. This principle lasted for decades until it was challenged and ultimately overturned by the Supreme Court's decision in Brown v. Board of Education in 1954, which held that separate educational facilities are inherently unequal and therefore unconstitutional.