The legal case that established the principle of "separate but equal" in U.S. education is Plessy v. Ferguson, decided by the Supreme Court in 1896. This case arose when Homer Plessy, an African American man, challenged a Louisiana law mandating racial segregation in public facilities. The Court upheld the law, ruling that racial segregation was constitutional as long as the separate facilities were "equal." This decision legitimized racial segregation and discrimination, profoundly impacting American society and institutionalizing segregation in schools, transportation, and other public spaces until it was overturned by Brown v. Board of Education in 1954.